Economic models at the Bank of England September 2000 update Bank of England Any enquiries about this publication should be addressed to: Meghan Quinn Monetary Analysis Telephone 020-7601 5269 Fax 020-7601 5196 email: [email protected] Further copies of this publication are available from: Publications Group Telephone 020-7601 4030 Fax 020-7601 3298 email: [email protected] The Bank’s Internet pages are at http://www.bankofengland.co.uk Bank of England, Threadneedle Street, London, EC2R 8AH. Printed by Park Communications Ltd © Bank of England 2000 ISBN 1 85730 182 X Contents Page 1 1.1 1.2 1.3 1.4 Introduction Models, policy analysis and forecasting General characteristics of the macroeconometric model Changes to the MM Other models added to the suite 5 5 6 7 8 2 Overview of the macroeconometric model 9 3 3.1 3.2 3.3 The structure of the macroeconometric model The long-run real growth path The long-run nominal growth path and inflation Short-run dynamics and inflation 10 10 13 14 4 Recent changes to the model specification 15 5 5.1 5.2 5.3 Simulation properties Rationale for simulations Temporary interest rate shock Exogenous change in a price level target 16 16 17 18 6 6.1 6.2 6.3 6.4 6.5 6.6 Detailed equation listing Money, financial and wealth variables Demand and output Labour market Prices Fiscal policy Income 20 21 27 36 42 54 56 7 Variables listing 59 Bibliography 68 The macroeconometric model 1 5 Introduction In April 1999, the Bank of England published Economic Models at the Bank of England, setting out the economic modelling tools that help the Monetary Policy Committee (MPC) in its work. That volume included a complete listing of the Bank’s main macroeconometric model (MM), and outlined the other members of the suite of models used for various aspects of monetary policy analysis. It was made clear at the time that neither the MM nor the other models in use should be thought of as fixed in form or content. Indeed, many aspects of the models are regularly reviewed, and new approaches to modelling aspects of the economy are continually investigated. The purpose of this publication is to provide an update of the changes incorporated in the MM over the past 18 months. It provides a written listing of the MM, to accompany the simultaneous release of the model code in electronic form. At the same time, we reference some other work within the Bank that has added to the range of models in the suite and that is already publicly available. In this section we outline the Bank’s modelling philosophy (set out more fully in the earlier volume), describe the key features of the MM, highlight the main ways in which the MM has changed since April 1999, and outline some other relevant modelling work. Sections 2 and 3 explain the structure of the MM in more detail. Section 4 outlines the changes to the MM. Section 5 discusses the MM simulation properties. Finally, Sections 6 and 7 provide a complete model listing, including diagnostics on estimated equations and data sources. 1.1 Models, policy analysis and forecasting The MM is the main tool for producing projections of GDP growth and inflation shown in the Inflation Report. The MM is built around a number of estimated econometric relationships, but some of the model properties—notably the long-run properties—are imposed in the form of parameter restrictions for theoretical consistency. There is a continual need to evaluate and update various components of the MM. Estimated MM econometric relationships may have broken down or have changed in some way, so that research is required to investigate the causes and to test alternatives that may eventually be incorporated in the MM itself. The Bank continues to use a range of models. Some provide inputs into the quarterly projections, while others are used to analyse specific policy questions that cannot be handled adequately within the MM. Some research may prove difficult or impossible to incorporate in the MM—for example, it may involve a different level of aggregation. It would then be run in parallel to provide a comparison with MM outputs, or to provide insights into aspects of the economy that the MM cannot address. Occasionally, specific new policy issues arise that cannot be analysed using the existing framework, and models are set up specifically to examine the key features of the issue at hand. Examples have included the impact of the National Minimum Wage, the implementation of the Working Time Directive, and the assessment of the impact on consumer spending of the windfalls 6 Economic models at the Bank of England from building society demutualisations. In some cases, a purpose-built model may cease to be of use once the issue it addresses no longer has monetary policy significance. But in other cases the work is incorporated in tools that are used to assess issues of continuing relevance. Each forecasting round requires assumptions to be made about a wide range of exogenous variables. Auxiliary models are often used to inform these judgments. Some relate, for example, to the world economy or some element of it, such as commodity prices or the level of world trade. For the assessment of world economic activity and inflation, the MPC uses a model(1) of the world economy provided by the National Institute of Economic and Social Research to help form its judgments. Other models relate to aspects of the domestic economy that are not formally modelled in the MM, but where parameters may be varied or restricted as a result of the auxiliary analysis. In all cases, the assumptions incorporated in any specific forecast are a combination of those suggested by the auxiliary model and the application of the MPC’s judgment. Profit margins and house prices are examples of areas where forecast assumptions are influenced by both supplementary modelling and MPC judgment. Where the Bank does not have the tools to hand for analysing a specific issue, it will seek out the best available analysis from the academic literature or from the research work of other central banks and research institutes. For this reason, Bank staff are encouraged to keep abreast of the relevant academic literature and to contribute to it by publication of working papers, contributions to professional journals, and presenting their work at conferences. The Bank also runs a seminar series, addressed both by outside experts and by internal staff. The general philosophy with which the Bank approaches modelling and forecasting in particular, and monetary policy analysis in general, is one of pluralism and openness. We are happy to receive comments on this and on any other publication, particularly suggestions on how things could be improved. 1.2 General characteristics of the macroeconometric model The core macroeconometric model (MM) consists of about 20 key equations determining endogenous variables. There are a further 90 or so identities defining relationships between variables, and there are about 30 exogenous variables whose paths have to be set, as discussed above. GDP is determined in the short term by the components of aggregate demand—private consumption, investment (including inventory investment), government consumption, and net exports. In the longer term GDP is determined by supply-side factors, which determine potential output. Domestic firms are modelled as producing a single composite good using an aggregate production function of the Cobb-Douglas form. So output is determined in the long run by the evolution of the capital stock, the labour supply and total factor productivity. These variables are assumed to be unaffected by the price level or the inflation rate (so the model exhibits long-run monetary neutrality and super-neutrality). (1) The National Institute Global Economic Model (NiGEM). The macroeconometric model 7 Price level dynamics and the adjustment of actual output towards potential are broadly determined by the interaction between aggregate demand and supply, augmented by explicit relationships for aspects of wage and price-setting. These relationships are consistent with the view that firms set domestic output prices as a cyclically varying mark-up over unit labour costs. RPIY is determined by an equation linking retail prices to domestic output prices and import prices. Firms are also assumed to determine the level of employment, and real wages are determined by bargaining in an imperfectly competitive labour market. Inflation expectations have an explicit role in wage determination. But price responses are sluggish, so there is slow adjustment towards both real and nominal equilibria. The appropriate assumptions under which to run the model depend on the exercise at hand. For example, short-run forecasting typically requires different assumptions from those used for long-run simulations, and for either purpose a wide range of alternative assumptions could be made. For the main Inflation Report forecasts, nominal short-term interest rates are assumed to be constant over the forecast period, but an alternative is also presented in which rates follow the path implied by market expectations. When using the MM for simulation purposes, the short rate can be set according to a policy rule linking short-term nominal interest rates to the monetary policy target, but the nature of this rule can take many different forms. Different exchange rate assumptions can be used in both the construction of projections and for simulations. A range of possible treatments is also available for the evolution of net financial wealth, and for inflation expectations. A further example of where different assumptions may be used for different purposes relates to government spending. The Inflation Report projections incorporate announced government spending plans, but some alternative assumption is needed in longer-term simulations, as spending plans are not announced for more than a few years at a time. In this case, a common assumption is that government consumption growth is fixed in either nominal or real terms. The properties of the model when used for simulation purposes are shown in Section 5 below. 1.3 Changes to the MM The main areas of the MM in which changes have been introduced since April 1999 are: ● The consumption function now incorporates a new measure of labour income, which includes self-employment incomes (mixed incomes). Gross housing wealth and net financial wealth now have a separate role in the dynamics. And the real (short) interest rate matters in the long run, while nominal short rates affect the dynamics. ● There is a new equation for house prices, which depend on average earnings and the long real rate in the long run, while GDP enters the dynamics (in addition to earnings). ● Both export and import equations have been modified as a result of estimation on new data, the main effect being to lower slightly the relative price elasticities. 8 ● Economic models at the Bank of England RPIY is determined by a modified relationship that weights domestic and import prices. In addition, there are other small modifications resulting from data revisions and definitional changes affecting the capital stock, investment, trade prices, earnings, employment, non-labour income and the GDP deflator. There are minor changes to the treatment of value-added tax and special duties (affecting the link from RPIY to RPIX), and a new equation for the government expenditure deflator has been introduced. These changes are discussed more fully in Section 4. The detailed specification of the current model is set out in Section 6. The simulation properties of the MM, in terms of both timing and scale of responses, have not been affected substantially by the recent changes. For example, an unanticipated change in the short-term interest rate for four quarters still has its maximum impact on inflation after about nine quarters, and the order of magnitude is similar to that shown in the earlier publication. The current MM suggests that unanticipated changes in interest rates have a slightly faster impact on real GDP than the earlier version, with the peak impact being felt after four rather than five quarters. The size of the impact is comparable with the earlier version of the MM. 1.4 Other models added to the suite There has been a large amount of work within the Bank of England over the past two years designed to throw light on specific monetary policy related issues. Some of this research feeds into the background analysis prepared as input to the quarterly forecasting round, while other work feeds into monthly briefings to highlight specific issues on an ad hoc basis. Specific examples can be found in the papers published in the Bank’s working paper series. A selection of such research is highlighted here. ● A series of papers has investigated the impact of model uncertainty on actual and optimal monetary policy.(1) ● Further work using structural vector autoregressions has been done, following on from research discussed in Chapter 5 of the 1999 volume. One example was aimed at identifying monetary policy shocks from the many other shocks that hit the economy, by imposing a priori restrictions.(2) Another example used related methods to investigate the empirical relationship between different measures of ‘gaps’ (output, employment and capacity utilisation) by the imposition of restrictions implied by economic theory.(3) ● Small-scale aggregated models (as discussed in Chapter 4 of the 1999 volume) have also been used to investigate the relationship between optimal monetary policy and inflation projections.(4) (1) (2) (3) (4) Hall, Salmon, Yates and Batini (1999); Martin and Salmon (1999); and Martin (1999). Dhar, Pain and Thomas (2000). Astley and Yates (1999). (This paper was mentioned in the April 1999 publication, but was published subsequently.) Batini and Nelson (2000). The macroeconometric model 9 ● Optimising models (of the type outlined in Chapter 6 of the 1999 volume) have been used to investigate several issues of relevance to monetary policy. For example, one model has been used to investigate the determinants of the changing behaviour of mark-ups over time.(1) Another paper has examined the potential impact of the labour market reforms of the 1980s on the wage-setting and employment decisions of firms.(2) ● Further work has been done on the Phillips curve type models discussed in Chapter 3 of the 1999 volume; this work may be published in due course. ● There has also been considerable work on developing tools for extracting and interpreting information from financial markets, for example about interest rate and inflation expectations.(3) For the remainder of this publication we focus entirely on the MM, how it has been developed and its properties. 2 Overview of the macroeconometric model The macroeconometric model contains around 20 estimated econometric equations. These are supplemented by identities, transformations and linking equations. Including exogenous variables, there are about 140 variables in the model database.(4) The MM has three key features. (i) A long-run growth path for real output, consistent with the following properties: ● price level neutrality: the long-run real growth path is independent of the price level. This is ensured by restricting equations containing nominal variables to exhibit static homogeneity. ● inflation neutrality: the long-run real level of output and the unemployment rate are independent of the inflation rate, ie the long-run Phillips curve is vertical. To ensure that this holds, equations containing nominal variables are restricted to satisfy dynamic homogeneity, and inflation expectations are constrained to converge on actual inflation in the long run. (ii) A long-run growth path for nominal (ie money-denominated) variables, determined by an anchor specified in terms of a target for a nominal variable (for example an inflation or a price level target). This nominal anchor is usually secured by choosing a feedback rule for monetary policy linking the instrument of monetary policy (short-term nominal interest rates) to the selected target. Though the quantity of money does not have a causal role in this set-up (over and above the inter-temporal price of money, ie interest rates) the money (1) (2) (3) (4) Britton, Larsen and Small (2000). Millard (2000). Anderson and Sleath (1999); Clews, Panigirtzoglou and Proudman (2000); and Bliss and Panigirtzoglou (2000). See the variables listing in Section 7. 10 Economic models at the Bank of England supply will move in line with nominal output in the long run, in the absence of persistent shifts in velocity. (iii) Sluggish adjustment of nominal and real variables to economic shocks. Goods and labour markets are characterised by both real inertia (quantities take time to adjust to economic shocks) and nominal inertia (prices do not move immediately in response to changing economic conditions), which results in slow adjustment of the economy towards its long-run growth path. The speed of adjustment reflects the degree of inertia in the wage-price system, and the costs of adjusting employment or the capital stock. 3 The structure of the macroeconometric model This section discusses the structure of the MM in more detail. We follow the three stages described above, by characterising the real and nominal long-run growth paths and the dynamic response of the economy when it is away from these paths. All variables are expressed in logs, unless otherwise stated.(1) Equation coefficients are written as Greek letters; for example intercept coefficients are written as βz for the equation in which z is the dependent variable. A full description of these and all the other model equations is given in Section 6. 3.1 The long-run real growth path The core of the model’s supply side consists of four variables: output, labour (defined in terms of hours worked), the capital stock (defined in terms of non-housing capital), and real wages. Long-run output is determined by a simple Cobb-Douglas production function with constant returns to scale and diminishing marginal returns to each factor of production, which can be written as: y = βy + αµ T + α l + (1 – α)k (3.1.1) where output (y) is produced by combinations of capital (k), labour (l) and labour-augmenting technical progress (µ T), which is assumed to be exogenous.(2) Firms are assumed to choose labour and capital so as to maximise their profits. This implies the following marginal revenue/product conditions with respect to labour and capital: y – l = βl + w – pd (3.1.2) y – k = βk + rc (3.1.3) where w is the nominal wage, pd is the domestic product price (ie the GDP deflator), rc is the real cost of capital, and the long-run constants capture, among other things, the production technology and the degree of competition in product and labour markets. (1) (2) The convention adopted throughout is for variables to be assigned upper-case and their logs to be assigned lower-case letters. The parameter α is set at 0.7, consistent with the observed average share of income going to labour. The macroeconometric model 11 Equation (3.1.1) can be expressed as a labour demand equation as in (6.3.11) below by writing employment on the left-hand side. Equation (3.1.2) can be expressed as either a labour demand curve, by writing employment on the left-hand side, or as a price mark-up equation, with prices on the left-hand side. In the equation listing in Section 6, it is expressed as a price mark-up over unit labour costs (6.4.1). In the long run this mark-up is assumed constant. Together with the assumption of Cobb-Douglas technology this implies that long-run factor shares are also constant. Equation (3.1.3), expressed as the business investment equation (6.2.12), and the capital accumulation equation (6.2.11) together describe the investment/demand-for-capital relationship. Wage-setting behaviour is consistent with an imperfectly competitive model of the labour market, where firms bargain with workers over real wages, but set goods prices and employment levels (see, for example, Layard, Nickell and Jackman (1991)). The real wage equation (3.1.4) which is estimated in equation (6.3.3) implies that, in the long run, real unit labour costs depend positively on a set of structural variables (Zs) (such as union power and the replacement ratio) and negatively on the unemployment rate (U):(1) w – pd = βw + y – l + θ1Zs – θ2U (3.1.4) where the rate of unemployment is defined as the active working population minus employment as a proportion of the active working population by headcount (6.3.8). The link between employment in terms of total hours worked and in terms of the number of people in work is given by a relationship for average hours (6.3.13). Equation (3.1.2) and (3.1.4) both define alternative expressions for the labour share that must be consistent in the long run. By substituting equation (3.1.2) into (3.1.4) and rearranging, the long-run unemployment rate (U*) can be expressed as: U* = (βl + βw + θ1Zs) / θ2 (3.1.5) In a closed economy, aggregate demand and supply cannot, by definition, diverge from each other. But in an open economy such as the United Kingdom, aggregate demand can be met from overseas as well as from domestic supply, and domestic supply can be sold overseas to meet foreign demand. So a stylised IS-curve model of aggregate demand can be written as: yd = βy + γ1y + γ2yw + γ3r + γ4x d (3.1.6) where aggregate demand, yd, depends on domestic income (y), overseas income (yw), the real interest rate (r) and the real exchange rate (x), which will affect the share of domestic and overseas demand being spent on UK output. (1) In all the supply-side equations, labour costs include employers’ taxes. 12 Economic models at the Bank of England Summing the expenditure components of GDP determines aggregate demand: ● consumption (6.2.8) is modelled in the long run as a function of labour income, wealth and real interest rates; nominal interest rates are included in the short-run dynamics to proxy for confidence and cash-flow effects; and the change in unemployment is used to capture influences on precautionary saving; ● investment (6.2.11 and 6.2.12) is consistent with equation (3.1.3) above, and determines the stock of capital; ● stockbuilding (6.2.16 and 6.2.17) over the medium term is consistent with a downward trend in the long-run stock-output ratio; ● real government spending (6.2.15) is treated as exogenous in the simulations outlined in Section 5. But announced nominal government spending plans provide the basis for forecasting this component (with real government spending influenced by the projection for inflation); ● exports (6.2.18) depend on world trade volumes (weighted by UK market shares) and a measure of the real exchange rate, which reflects the competitiveness of UK exports; and ● imports (6.2.19) are modelled as a function of domestic demand, a competitiveness term, and a proxy measure for the increase in gross trade flows relative to world demand arising from increased globalisation and international specialisation. As the United Kingdom is an open economy, aggregate demand is brought into line with potential supply in the long run by movements in the real exchange rate, via a combination of changes in the nominal exchange rate and domestic price level for a given path for foreign prices. For simulation purposes, the nominal exchange rate (st) (6.1.6) is typically determined by the uncovered interest parity condition.(1) This relates expected changes in the exchange rate between two currencies to differences in their interest rates and a risk premium. This can be written as: st = set+1 + it – iwt – ρt (3.1.7) where st is defined as the number of units of foreign currency per unit of domestic currency, se is the expected value of the nominal exchange rate, i and iw are the domestic and foreign one-period nominal interest rates respectively, and ρ is the risk premium. This relationship can be written equivalently as a relationship expressing the real exchange rate in terms of real interest rates: xt = xet+1 + rt – rwt – ρt (1) (3.1.8) Since November 1999 the central projection in the Inflation Report has assumed that the nominal exchange rate evolves along a path halfway between a constant rate and the path implied by the uncovered interest parity condition, conditioned on constant UK interest rates, with a zero risk premium. The macroeconometric model 13 where rw is the world real interest rate. This implies that, in the long run, UK real interest rates would differ from world real interest rates by the risk premium, if the long-run real exchange rate were constant. 3.2 The long-run nominal growth path and inflation The long-run levels of output and employment described above are independent of both the price level and the rate of inflation. This reflects the theoretical presumption and empirical evidence that there is no long-run trade-off between inflation and the level of output or employment. The MM has several measures of prices: ● the domestic output price index (the GDP deflator at factor cost, pd) (6.4.1) is modelled as a mark-up over unit labour costs, as described above; ● the RPIY price index (RPI excluding indirect and council taxes, and mortgage interest payments) (6.4.5) is modelled as a weighted average of domestically consumed output prices and import prices; ● RPIX (6.4.6) is then modelled by adding indirect and council taxes to RPIY; ● the retail price index (RPI) (6.4.11) is obtained by adding mortgage interest payments to RPIX; ● the consumers’ expenditure deflator (6.4.13) is assumed to grow in line with RPIX excluding council taxes; ● the government consumption deflator (6.4.14) is assumed to grow in line with the average of retail prices, excluding mortgage interest payments and council taxes, and unit labour costs; ● import prices (6.4.2) are assumed in the long run to be set by foreign suppliers in world markets, with their sterling value determined by the nominal exchange rate; and ● export prices (6.4.3) reflect a weighted average of domestic costs, exchange rate adjusted world prices, and oil prices. The level and rate of change of the overall price level are determined by monetary policy in the medium term. This can be modelled in the form of a policy rule, linking the instrument of monetary policy (short-term nominal interest rates) to the monetary policy target. In principle, any nominal variable can act as a target for monetary policy, for example an inflation target or a price level target. A variety of policy rules can be used. In the United Kingdom, the government’s inflation target is defined in terms of RPIX inflation. The MM allows this type of policy regime to be captured by a 14 Economic models at the Bank of England rule in a variety of ways. One common formulation is that developed by Taylor (1993). A version of this is expressed in equation (3.2.1), where nominal interest rates (i) are set with reference to some ‘equilibrium’ real interest rate (rt*), the current annual inflation rate πt, the deviation of the current annual inflation rate from the inflation target (πt – πt*), and the excess of actual output over potential (y – y*):(1) it = πt + rt* + λ1(πt – πt*) + λ2(yt – yt*) (3.2.1) In this simple rule, the responsiveness of nominal interest rates to deviations of inflation from target and output from potential is determined by the weights λ1 and λ2. Such rules usually ensure that inflation converges on its target rate in the long run. An alternative simple price level target rule is also used in some of the simulations described later in Section 5. This specifies that nominal interest rates (it) are set with reference to the equilibrium real interest rate (rt*), the current annual inflation rate πt and the deviation of the actual price level from some target price level (pt – pt*). One form of such a rule is: it = πt + rt* + λp (pt – pt*) (3.2.2) where λp determines the responsiveness of nominal interest rates to the deviation of the price level from target. As long as λp is above zero, this rule should ensure that the price level converges on its target trajectory in the long run. The monetary policy rules adopted in the simulations described below are purely illustrative, and can be varied according to the question being considered. They have no status as a guide to monetary policy in practice. 3.3 Short-run dynamics and inflation When on its long-run growth path, output grows in line with supply potential (determined by technology and factor supplies), and inflation is determined by the stance of monetary policy. The relationships that characterise this long-run growth path are embedded in equilibrium-correction terms in dynamic equations that ensure that these relationships reassert themselves gradually in the face of economic shocks. Often, theoretical reasoning has more to say about long-run relationships than about how quickly the economy should return to its long-run growth path following shocks. So, unlike the long-run properties, which are almost always imposed to reflect economic theory, the short-run dynamics are more often empirically estimated to match average historical behaviour. Output and inflation diverge from their long-run growth paths because of different kinds of inertia, which are reflected in the equations of the MM. There are two main types: (1) The ‘output gap’ measure used in the Taylor rule in the MM defines potential output as the output that would be implied by a Cobb-Douglas production function at the current level of capital input, potential labour inputs, and exogenous labour-augmenting technical progress. The macroeconometric model 15 ● real inertia, which restrains real variables from moving immediately to their long-run values, for example because of the costs of adjusting employment or the capital stock; and ● nominal inertia, which restrains prices from adjusting immediately in the face of shocks. One example is the assumption that wage contracts are fixed for one year, and so do not respond quickly to unanticipated developments (see Section 6.3.1). Another is that there may be costs associated with changing prices. When inertia is present, the economy can deviate for some time from its long-run real and nominal growth paths in the face of shocks. Deviations of output from its long-run growth path will tend to be associated with changes in inflationary pressure. If the economy is operating above its potential output level, inflationary pressure will tend to rise, other things being equal, and conversely if activity is below potential. In practice, it is difficult to judge with any precision where activity stands in relation to capacity. One useful conceptual framework for thinking about inflationary pressure is a short-run Phillips curve.(1) Although it is not possible to derive a Phillips curve analytically from the complex dynamic wage-price system in the MM, it is possible to explore influences on inflation in the MM by running a variety of simulations. 4 Recent changes to the model specification As with any macroeconometric model, the MM does not have a fixed specification and is being continually developed. These developments may reflect new data or, more generally, new analysis of a particular sector of the economy. Since the publication of the MM in April 1999 there have been a series of small revisions to equation specifications in the light of new data. These new data reflect not only the regular stream of quarterly data, but also periodic revisions to past series, for example the re-grossing of the labour market statistics and revisions to the National Accounts data contained in the Blue Book. Such changes to the data require the relevant equations to be re-estimated to check that historical relationships remain valid. Often these revisions do not require alterations to the basic structure of the equation, but can lead to different estimated coefficients in the equation. Equations where coefficients have been modified slightly due to new data include: real wages (6.3.3), domestic output prices (6.4.1), import prices (6.4.2), export prices (6.4.3), households’ non-labour income (6.6.4), business investment (6.2.12), employment in hours (6.3.11), average hours (6.3.12), and trend output (6.2.5). In addition, there have been minor changes to the treatment of value-added tax and special duties tax, and a simple equation for the government expenditure deflator (6.4.14) has been introduced. These slight modifications have had no material impact on the simulation properties of the MM. Equations where there have been more significant changes to the coefficients include the volume equations for exports (6.2.18) and imports (6.2.19). A combination of new data and the more (1) For a more complete discussion of Phillips curve models see Chapter 3 of Bank of England (1999). 16 Economic models at the Bank of England recent behaviour of trade volumes suggests that the long-run real exchange rate elasticities for UK exports and imports are now lower than previously estimated. These modifications to the trade volume elasticities somewhat reduce the impact of changes in exchange rates on net trade. In addition to data revisions since the previous publication of the MM, there has been further analysis of the role of real wealth and interest rates in determining consumers’ real spending and the behaviour of house prices. The current version of the MM includes both a separate role for gross housing and net financial wealth in the short-run dynamics of the consumption function and a role for real interest rates in the long run (6.2.8). Complementing these changes to the consumption equation, the current version of the MM also includes a more detailed account of house price determination (6.4.15), although it is still relatively simple compared with single-equation specifications available in the academic literature. These modifications have marginally strengthened the channel from real interest rates to domestic demand. A further modification was aimed at simplifying the use of the MM in forecasting. In the April 1999 version, both RPIY and GDP deflator equations were jointly dependent on unit labour costs. This joint determination sometimes made the dynamics of the MM difficult to understand. For clarity, the MM specification was altered to simplify the transmission of certain shocks by separately identifying the price of output produced in the United Kingdom, including exports (6.4.1), and the price of output both consumed and produced in the United Kingdom, excluding exports (6.4.4). For some simulations the RPIY inflation is now modelled as a weighted average of domestic and import prices directly rather than relying on unit labour costs as a proxy for domestic prices. This modification marginally increases the speed of the MM’s price dynamics. 5 Simulation properties 5.1 Rationale for simulations Some of the properties of the MM can be assessed by examining sub-systems within it, or by analysing single equations. However, the properties of the model as a whole can best be understood by simulation analysis. The illustrative simulations presented here concentrate mainly on the behaviour of the nominal side of the model, and focus on the effects of nominal interest rate changes on the price level, inflation and output. As explained earlier, it is possible to run the model under a range of different assumptions. In particular, those adopted for forecasting may not be the same as those that are appropriate for longer-term simulations. For example, in MPC forecasts, it will typically be assumed that the government’s spending plans are set in cash terms.(1) But in longer-run simulations, it is more appropriate to assume that government spending is either exogenous in real terms or fixed as a share of output. (1) For example, see the discussion on page 53 of the May 2000 Inflation Report. The macroeconometric model 17 Other important assumptions relate to how expectations are formed. In the simulations described below, expectations of the exchange rate one period ahead are assumed to be formed in a forward-looking manner, consistent with the predictions of the model itself. This implies that the exchange rate will jump in response to unexpected changes in interest rate differentials or in the long-run exchange rate level. Other asset prices are not treated in a forward-looking manner, but are assumed to move in ways that are broadly consistent with the long-run growth path of the economy (for example, equity prices are assumed to grow in line with nominal GDP). Inflation expectations are assumed to exhibit a degree of inertia: wage-setters, for example, take time to respond to new information (see equation (6.4.16b)). Various assumptions can be made about the behaviour of monetary policy. For example, different interest rate rules can be used. Neither the stance of monetary policy nor the assumptions about how expectations are formed affects the real properties of the simulations in the long run, but they are both likely to have important effects on the dynamic responses of inflation and real activity in the shorter run. 5.2 Temporary interest rate shock In attempting to understand the transmission mechanism of monetary policy, it is helpful to simulate the effects of a change in nominal interest rates. In practice, interest rates are not changed in isolation but are altered in response to economic developments that require a monetary policy response. And the effect of any resulting change in interest rates will also depend on the policy regime—since this, in turn, will affect the behaviour of agents in the economy, for example via its effect on long-run inflation expectations and other asset prices. Given these considerations, we analyse below the effect of an unanticipated one-year positive 1 percentage point deviation in interest rates from a monetary policy rule. In these simulations, nominal interest rates continue to be affected beyond the first year, as interest rate changes are determined by the monetary policy rule. The monetary policy rule used for the purpose of this benchmark simulation is one in which nominal interest rates are set according to a Taylor rule of the type shown in equation (3.2.1). To illustrate the point that the simulation responses of inflation and output will depend on the specific assumptions made, we show three different simulations: ● First, the coefficients in the Taylor rule on the deviations of inflation from target and output from base are set at 0.5.(1) ● Second, the coefficient in the Taylor rule on the deviation of inflation from target is increased to 1.0, suggesting that the monetary authority responds more strongly to inflation deviations from target. (1) This coefficient choice was originally adopted in Taylor (1993). 18 Economic models at the Bank of England Third, the coefficient on the deviation of inflation from target in the Taylor rule is increased further to 1.5, suggesting that the monetary authority will respond even more strongly to inflation deviations from target. ● It would also be possible to vary other aspects of the simulation, for example by altering the assumptions about how expectations are formed. However, it should be emphasised that, even for a given set of assumptions, the effects of a change in interest rates are highly uncertain, because of uncertainty about the value of the parameters underlying the model and about the specification of the model itself. Charts 1(a) and (b) show the results for inflation and GDP respectively. The maximum effect of the temporary interest rate increase on real activity occurs after about one year, and the maximum effect on inflation occurs after about two years. For the benchmark simulation, where the Taylor rule with a weight of 0.5 on the deviation of inflation from target is adopted, the level of GDP falls by about 0.3% at the end of the first year, recovering to base after three years. Inflation remains broadly unchanged during the first year, reflecting the degree of nominal inertia in the economy, but by the beginning of the third year has fallen by just over 0.3 percentage points. Thereafter, it returns slowly to base. Simulation (i): Response to 1 percentage point rise in nominal interest rates for one year Chart 1(a) Chart 1(b) Annual RPIX inflation rate GDP level Difference from base, percentage points Difference from base, per cent 0.2 Taylor rule (1.0) 0.1 Taylor rule (1.5) 0.1 + + 0.0 0.0 – – Taylor rule (1.5) 0.2 Taylor rule (0.5) 0.1 0.1 0.2 0.2 0.3 0.3 Taylor rule (1.0) Taylor rule (0.5) 1 2 3 4 5 6 7 8 9 10 Quarters 11 12 13 14 15 16 0.4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Quarters 0.4 When a Taylor rule with a greater weight on deviations of inflation from target is adopted, the peak effect on inflation is similar to the benchmark case. But thereafter inflation returns to base more quickly as interest rates are adjusted more strongly in response to the temporary deviation of inflation from target. However, this more vigorous response of monetary policy results in a more volatile path for output, with GDP rising further above its long-run level before stabilising. 5.3 Exogenous change in a price level target The next simulation shows what could happen if there were an unexpected 1% permanent decrease in a nominal target for monetary policy defined in terms of the (RPIX) price level. Although this The macroeconometric model 19 simulation does not correspond to the current UK monetary policy framework, which is defined in terms of an inflation target, it is useful for testing and illustrating the nominal neutrality of the model (ie that the change in the nominal anchor has no long-run effect on real variables such as output and employment). The impact of such a decrease in a price level target will partly depend on the rule that monetary policy is assumed to follow. We assume that nominal interest rates are set according to a simple rule of the type shown in equation (3.2.2). To illustrate the impact of different policy rules, Table A shows simulation results when the coefficient on the deviations of the price level from target is set at 0.25, 0.50 and 0.75 respectively. The initial price level gap is reflected directly in nominal interest rates, which rise in all cases by between 1/4 and 3/4 percentage points immediately, before falling below base by the third year. Real interest rates remain above base levels for as long as RPIX is above its new target level. Output falls by a maximum of between 0.1% and 0.3% at the end of two years, before returning close to base level after about four years. The MM exhibits a smooth and gradual adjustment to its long-run path when the Taylor rule is used in the simulations above, but this is not the case when the simple price level target rule is used to close the MM. While RPIX falls to its new target level over four years it does not do so smoothly. Instead, the MM response to this shock is characterised by a dampened cyclical pattern. Despite this cyclical pattern, the simulation results show the long-run nominal neutrality of the model: all real variables return to their long-run values and all nominal variables fall by 1%. Table A Simulation (ii): Response to 1% fall in price level target Percentage or percentage point (pp) difference from base 1 quarter Feedback coefficient on p-p* Variable RPIX level (%) RPIX annual inflation (pp) Nominal interest rate (pp) Real interest rate (pp) (b) GDP (%) Real exchange rate (%) Consumer spending (%) Investment (%) Exports (%) Imports (%) 2 years 4 years Steady state (a) 0.25 0.50 0.75 0.25 0.50 0.75 0.25 0.50 0.75 -0.03 -0.03 0.24 0.27 -0.03 0.75 -0.04 0.00 -0.05 -0.04 -0.04 -0.04 0.48 0.52 -0.05 1.01 -0.08 0.00 -0.07 -0.09 -0.05 -0.05 0.72 0.77 -0.06 1.21 -0.12 0.00 -0.09 -0.13 -0.16 -0.12 0.13 0.24 -0.14 0.15 -0.15 -0.31 -0.06 -0.14 -0.22 -0.18 0.27 0.45 -0.22 -0.10 -0.28 -0.56 -0.05 -0.30 -0.27 -0.23 0.40 0.63 -0.30 -0.41 -0.40 -0.80 -0.02 -0.45 -0.66 -0.28 -0.19 0.09 -0.07 -0.35 -0.06 -0.40 0.03 -0.08 -0.98 -0.42 -0.40 0.02 -0.05 -0.83 -0.03 -0.61 0.11 -0.11 -1.24 -0.53 -0.72 -0.19 0.01 -1.21 0.05 -0.73 0.20 -0.07 -1.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (a) The MM has been constructed to ensure that these steady-state responses are obtained. (b) Here the real interest rate is defined as rt = it – π et, where π et = πt. All the simulations shown above illustrate the monetary transmission mechanism within the model by which changes in nominal interest rates bring about changes in the price level. There are three main channels: 20 Economic models at the Bank of England ● First, the real exchange rate appreciates on impact by around 1%, before depreciating back towards its base value.(1) This initial jump reflects the anticipated cumulative policy-induced rise in the real interest rate over the entire simulation. The short-term appreciation has a direct effect on domestic prices, partly through the influence of import prices on retail prices and partly through the temporary effect of the real exchange rate on real wages. There is also an indirect effect on prices via net trade. Exports initially fall by around 0.1% before recovering as the real exchange rate falls back. Imports are stimulated by the fall in competitiveness, but this is outweighed by the effects of the fall in domestic demand. The net impact is for imports to fall by 0.3% after two years. ● Second, higher nominal interest rates result in the stock of net financial wealth being devalued. That, together with the short-term confidence effects, results in lower consumption in the short run. Consumption falls by about 0.3% after two years. Further out, this is offset by a terms-of-trade effect on income and by a wealth effect associated with the exchange rate appreciation. ● Third, there is the effect of real interest rates on investment and consumption, with investment falling by about 0.6% at the end of two years. In the longer run, investment recovers to bring the capital stock back towards its long-run level, but this occurs slowly because of the protracted response of investment in the model. Similarly, as real interest rates and wealth return to their long-run level, consumption also returns to its long-run level. 6 Detailed equation listing This section describes, in detail, the equations that form the Bank’s macroeconometric model (MM). It is important to note that the equations outlined in this section have been developed as part of the overall structure of the MM. The structure of the equations, the short-run and long-run restrictions placed on the coefficients, the available set of variables and the choice of data have all been dictated by the structure of the MM. The criteria for selection of a particular equation include the equation’s statistical properties and its impact on the overall MM simulation properties. For these reasons the individual equations outlined in this section should not be viewed as the ‘best’ single equations estimated: they are part of a system of equations that form the MM. From time to time alternative equations are developed and examined as part of the MM structure. They may be used to examine the impact of alternative economic theories, or the impact of relaxing some of the restrictions placed on the equations. Several conventions are used in the presentation of the equations in this section. Lower-case letters indicate natural logs. The subscript t denotes time: data are quarterly. ∆ indicates a first difference. Q1, Q2, Q3 and Q4 denote seasonal dummies. Each relationship is written so as to distinguish the long-run solution of the equation from the short-run dynamics. Long-run solutions (1) This description of the transmission mechanism applies to all the simulations shown, but the quantitative results apply to the price level target shock with a monetary policy rule of the form (3.2.2), with the feedback parameter set to 0.5. Altering assumptions under which the simulations are performed may alter the transmission mechanism as described here. For example, the transmission mechanism might differ if inflation expectations were assumed to evolve differently or if real interest rates were assumed to be affected by temporary monetary policy shocks. The macroeconometric model 21 appear in square brackets, and follow from the usual practice of estimating error-correction models. T-values are shown in parentheses, where applicable. Single-equation dynamic responses are given for some key variables. A standard set of diagnostic tests is shown, with the probability values for the diagnostic tests given in square brackets. Definitions and data sources for all model variables are given at the end of the equation listing. Bold numbers in brackets are cross-references to equations. 6.1 6.1.1 Money, financial and wealth variables Three-month interest rate (RS) The usual settings are either an exogenous constant nominal rate or market interest rate path (the alternative conditioning assumptions in Inflation Report projections), or a simple form of the Taylor rule linking the short-term nominal interest rate to the monetary policy target variable. RSt = INFt + Θ 0 + Θ1( gdpt − gdptt ) + Θ 2 ( INFt − ZPSTAt ) (6.1.1) where RS = base rate of interest (6.1.1). INF = four-quarter inflation rate of RPIX. GDPT = trend output (6.2.5). GDP = GDP(A) at factor cost (6.2.1). ZPSTA = Government inflation target (exogenous). Θ0, Θ1 and Θ2 are parameters to be set by the user. A variant of the rule links short nominal rates to a price level target. ( RSt = INFt + Θ 0 + Θ1( gdpt − gdptt ) + Θ 2 rpixt − rpixt* ) (6.1.1a) where RS = base rate of interest (6.1.1). INF = four-quarter inflation rate of RPIX. GDPT = trend output (6.2.5). GDP = GDP(A) at factor cost (6.2.1). RPIX = RPI excluding mortgage interest payments (6.4.6). RPIX* = target level for RPIX (exogenous). 6.1.2 Twenty-year bond rates (RL) For simulation purposes, long rates are set by reference to current short rates. RLt = RSt where (6.1.2) 22 Economic models at the Bank of England RL = 20-year bond yield (6.1.2). RS = base rate of interest (6.1.1). 6.1.3 Mortgage interest rates (RMM4) Mortgage interest rates affect the mortgage interest payment sub-index of the RPI. They are proxied by a constant mark-up over a weighted average of current and lagged short-term interest rates. Lagged rates are used to reflect some of the delay between official rate changes and their pass-through to mortgage borrowers. Both the weights and the mark-up were chosen to approximate past experience. () () RMM4t = 23 RSt + 13 RSt −1 + 1.0 (6.1.3) where RMM4 = mortgage interest rate (6.1.3). RS = base rate of interest (6.1.1). 6.1.4 Deposit interest rates (RD) Combined with the short-term interest rate, the deposit rate defines the opportunity cost of holding money. In the long run, it is equal to a proportion of the short-term rate (6.1.1). ∆RDt = 0.0572 − 0.28 ∆ RDt −1 + 0.75 ∆RSt + 0.24 ∆RSt −1 − 0.13[ RDt −1 − 0.7 RSt −1 ] (1.4) (−2.7) (17.4) (3.0) (6.1.4) (−2.8) where RD = deposit rate (6.1.4). RS = base rate of interest (6.1.1). Adjusted R2 = 0.80 Equation standard error = 0.38 LM test for serial correlation: F-stat. = 1.79 [0.17] Normality test: χ2(2) = 57.12 [0.00] Heteroscedasticity: F-stat. = 1.12 [0.36] Sample period: 1977 Q3–1998 Q2 6.1.5 Real cost of capital (RCC) Investment is affected by the real cost of capital (RCC). This reflects the rate of depreciation (on a quarterly basis), and the rates of both corporate taxation and investment allowances. As elsewhere in the model, inflation expectations relate to RPIX. ( ( 1 − PVICt 4 RCCt = 0.0025 RLt − INFEt + 100 1 − BETAt 1 − RCt where )) (6.1.5) The macroeconometric model 23 RCC = real cost of capital (6.1.5). PVIC = present value of investment allowances (exogenous). RC = effective corporate income taxation rate (exogenous). RL = 20-year bond yield (6.1.2). INFE = expectations of annual RPIX inflation (6.4.16). 1–BETA = business sector net capital stock depreciation rate (exogenous). 6.1.6 Nominal effective exchange rate (EER) For simulation purposes, the exchange rate is modelled using uncovered interest parity (UIP), with model-consistent expectations. eert = xeert + RSDF (6.1.6) where EER = sterling effective exchange rate index (6.1.6). XEER = expected sterling effective exchange rate (one period ahead). RSDF = interest rate differential (6.1.7). The interest rate differential is defined by: RS WRSt RSDF = log1 + t − log1 + 400 400 (6.1.7) where RS = base rate of interest (6.1.1). WRS = world nominal interest rate (exogenous). But under certain forecasting conditions the exchange rate is assumed to evolve along a path halfway between a constant rate and the path implied by the UIP condition, with backward-looking expectations and conditional on constant interest rates. For simulation purposes, the sterling-dollar exchange rate (EDS) is simply related to the effective rate. The constant reflects different units of measurement. edst = – 4.02 + eert (6.1.8) EDS = sterling-US dollar exchange rate (6.1.8). EER = sterling effective exchange rate index (6.1.6). 6.1.7 Real exchange rate (RXRX, RXRM and RRX) The exporters’ real exchange rate (RXRX) is the effective exchange rate deflated using relative export prices. The importers’ relative price (RXRM) is the price of imports relative to the GDP deflator. A further measure (RRX) relates the GDP deflator to world export prices. 24 Economic models at the Bank of England RXRXt = EERt .PXt WPXt (6.1.9) where RXRX = exporters’ real exchange rate (6.1.9). EER = sterling effective exchange rate index (6.1.6). WPX = world export prices (exogenous). PX = export price deflator (6.4.3). RXRMt = PMt PGDPt (6.1.10) where RXRM = importers’ relative price (6.1.10). PM = import price deflator (6.4.2). PGDP = GDP deflator at factor cost (6.4.1). RRXt = EERt .PGDPt WPXt (6.1.11a) where RRX = real exchange rate (GDP deflator measure) (6.1.11). EER = sterling effective exchange rate index (6.1.6). WPX = world export prices (exogenous). PGDP = GDP deflator at factor cost (6.4.1). To solve the model in forward-looking mode, it is convenient to express the UIP condition in real terms. rrxt = xrrxt + RSDFt + xwpxt + pgdpt − wpxt − xpgdpt (6.1.11b) where RRX = real exchange rate (GDP deflator measure) (6.1.11). XRRX = expected real exchange rate (one period ahead). RSDF = interest rate differential (6.1.7). XWPX = expected M6 export prices (one period ahead) (exogenous). PGDP = GDP deflator at factor cost (6.4.1). WPX = world export prices (exogenous). XPGDP = expected GDP deflator at factor cost (one period ahead). When the real exchange rate is determined in this way, the nominal exchange rate is obtained by inverting the identity for RRX in (6.1.11a). The macroeconometric model 6.1.8 25 Household sector wealth (WEL) Household sector wealth (WEL) is modelled in two parts: gross housing wealth and net financial wealth (GHW and NFW). WELt = GHWt + NFWt (6.1.12) Nominal housing investment is the flow into nominal housing wealth. The stock of nominal housing wealth is revalued in line with changes in house prices. PHSEt GHWt = ( PGDPt . IHt ) + GHWt −1 PHSEt −1 (6.1.13) where GHW = gross housing wealth (6.1.13). PGDP = GDP deflator at factor cost (6.4.1). IH = private sector dwellings investment (6.2.13). PHSE = UK house prices (6.4.15). Saving is the flow into nominal net financial wealth. The stock of net financial wealth is revalued in line with changes in asset prices (REV). NFWt = PCt ( RHPIt − Ct − IHt ) + NFWt −1. REVt (6.1.14) where NFW = net financial wealth (6.1.14). PC = total final consumers’ expenditure deflator (6.4.13). RHPI = real household post-tax income (6.6.5). C = consumers’ expenditure (6.2.8). IH = private sector dwellings investment (6.2.13). REV = wealth revaluation term (6.1.15). The weights in the revaluation term were derived from the household sector balance sheet (in Financial Statistics) and reflect the relative importance of foreign assets, gilts, interest-bearing deposits and equities in net financial wealth. EERt −1 WEQPt EERt −1 RLt −1 REVt = 0.045 + 0.12 + 0.01 + 0.15 EERt WEQPt −1 EERt RLt EERt −1 USRLt −1 EQPt + 0.04 + 0.64 EERt USRLt EQPt −1 where REV = wealth revaluation term (6.1.15). EER = sterling effective exchange rate index (6.1.6). (6.1.15) 26 Economic models at the Bank of England WEQP = world equity prices (exogenous). RL = 20-year bond yield (6.1.2). USRL = US long bond rate (exogenous). EQP = equity prices (6.1.16). An alternative, used in forecasting, is to allow NFW to evolve in line with nominal GDP. Equity prices either evolve in line with a simple dividend growth model. (1 + ∆gdplt ) EQPt = 0.0007 (GDPLt ) ( RLt / 100 − ∆gdplt ) (6.1.16a) where EQP = equity prices (6.1.16). GDPL = GDP at factor cost in current prices (6.2.4). RL = 20-year bond yield (6.1.2). Or in line with nominal GDP, supplemented by an exogenous constant (risk premium). ∆eqpt = ∆gdplt + 0.02 (6.1.16b) where EQP = equity prices (6.1.16). GDPL = GDP at factor cost in current prices (6.2.4). RL = 20-year bond yield (6.1.2). The simpler nominal GDP growth equation (6.1.16b) was adopted for the simulations. 6.1.9 Broad money demand (M4) Real broad money holdings respond to activity, net financial wealth and interest rates. Money can be specified as the nominal anchor in a monetary policy rule for interest rates. ∆( m 4 − pgdp)t = 0.0077 + 0.33 ∆( m 4 − pgdp)t −1 + 0.45 ∆gdpmt − 0.28 ∆gdpmt −1 (4.2) (3.3) (3.1) (−1.8) − 0.037[ m 4t −1 − pgdpt −1 − gdpmt −1 (−1.9) − 0.60 (nfwt −1 − pgdpt −1 − gdpmt −1 ) (−77.6) − 0.022 ( RDt −1 − RSt −1 )] (−4.8) (6.1.17) The macroeconometric model 27 where M4 = broad money (6.1.17). GDPM = GDP(A) at constant market prices (6.2.3). PGDP = GDP deflator at factor cost (6.4.1). NFW = net financial wealth (6.1.14). RD = deposit rate (6.1.4). RS = base rate of interest (6.1.1). Adjusted R2: 0.28 Equation standard error: 0.011 LM test for serial correlation: F-stat. = 2.12 [0.13] Normality test: χ2(2) = 1.73 [0.42] Heteroscedasticity: F-stat. = 1.60 [0.14] Sample period: 1977 Q3–2000 Q1 6.2 6.2.1 Demand and output Gross domestic product (GDP, GDPM, GDPL) Expenditure-based GDP is an accounting identity, including domestic demand, imports, exports and the factor cost adjustment. GDPt = DDt + Xt – Mt – FCAt (6.2.1) where GDP = GDP(A) at factor cost (6.2.1). DD = total domestic expenditure (6.2.7). X = exports of goods and services (6.2.18). M = imports of goods and services (6.2.19). FCA = factor cost adjustment (6.2.2). The factor cost adjustment is an (estimated) function of GDP. fcat = –1.87 + gdpt (6.2.2) where FCA = factor cost adjustment (6.2.2). GDP = GDP(A) at factor cost (6.2.1). GDPM is expenditure-based GDP at constant 1995 market prices. GDPMt = GDPt + FCAt (6.2.3) 28 Economic models at the Bank of England where GDPM = GDP(A) at constant market prices (6.2.3). GDP = GDP(A) at factor cost (6.2.1). FCA = factor cost adjustment (6.2.2). Nominal GDP (GDPL) at factor cost is the product of GDP (6.2.1) and the GDP deflator (PGDP) (6.4.1). GDPLt = PGDPt .GDPt 6.2.2 (6.2.4) Trend GDP and capacity utilisation (GDPT, CAPU) Trend output is determined by an estimated Cobb-Douglas production function. The direct inputs are the non-residential capital stock, the level of population of working age and exogenous labour-augmenting technical progress captured by the time trend. gdptt = 0.063 + 0.3 knht + 0.7 powat + (0.70)(0.004) TIME (3.9) (6.2.5) (18.7) where GDPT = trend output (6.2.5). KNH = capital stock excluding residential housing (6.2.10). POWA = population of working age (exogenous). TIME = time trend. Adjusted R2: 0.94 Equation standard error: 0.033 LM test for serial correlation: F-stat. = 455.7 [0.00] Normality test: χ2(2) = 4.84 [0.09] Heteroscedasticity: F-stat. = 6.34 [0.00] Sample period: 1978 Q1–1997 Q4 Capacity utilisation is proxied by the residuals from the estimation of a production function where the direct inputs are employment measured in hours, the non-residential capital stock and labour-augmenting technical progress captured by the time trend. CAPUt = gdpt − 2.66 − 0.70 empht − 0.30 knht − (0.70)(0.004) TIME (288.0) where CAPU = capacity utilisation (6.2.6). GDP = GDP(A) at factor cost (6.2.1). EMPH = total employment in hours (6.3.11). ( −34.1) (6.2.6) The macroeconometric model 29 KNH = capital stock, excluding residential housing (6.2.10). TIME = time trend. Adjusted R2: 0.98 Equation standard error: 0.018 LM test for serial correlation: F-stat. = 171.6 [0.00] Normality test: χ2(2) = 2.87 [0.24] Heteroscedasticity: F-stat. = 4.94 [0.00] Sample period: 1979 Q1–1998 Q4 6.2.3 Domestic demand (DD) Domestic demand is determined by an accounting identity, as the sum of consumers’ expenditure, investment, government consumption and stockbuilding. DDt = Ct + It + Gt + IIt (6.2.7) where DD = total domestic expenditure (6.2.7). C = consumers’ expenditure (6.2.8). I = fixed investment (6.2.9). G = general government final consumption expenditure (exogenous), (see Section 6.2.10). II = net stockbuilding (6.2.16). 6.2.4 Consumers’ expenditure (C) In the long run, consumers’ expenditure is a function of wealth, labour income and real interest rates. Nominal rates are included in the short run of the equation to capture confidence and cash-flow effects of changes in the stance of monetary policy. Changes in the unemployment rate are also included, to capture precautionary saving influences. ∆ct = − 0.036 + 0.19 ∆lyt + 0.052 ∆( ydijt −1 − pct −1 ) − 0.068 ∆urt −1 + 0.14 ∆( ghwt − pct ) ( −2.7) (3.6) ( −3.5) (4.0) (4.8) + 0.014 ∆(nfwt − pct ) − 0.0016 ∆RSt − 0.0017 ∆RSt −1 (1.3) ( −2.4) ( −2.8) − 0.17[ct −1 − 0.89 lyt −1 − 0.11( welt −1 − pct −1 ) + 0.0028 ( RSt − 2 − INFEt − 2 )] ( −4.3) (3.6) (2.3) where C = consumers’ expenditure (6.2.8). LY = real post-tax labour income (6.6.6). YDIJ = non-labour income (6.6.4). PC = total final consumers’ expenditure deflator (6.4.13). (6.2.8) 30 Economic models at the Bank of England UR = rate of unemployment (6.3.8). GHW = gross housing wealth (6.1.13). NFW = net financial wealth (6.1.14). WEL = total household sector wealth (6.1.12). RS = base rate of interest (6.1.1). INFE = expectations of annual RPIX inflation (6.4.16). Adjusted R2: 0.73 Equation standard error: 0.006 LM test for serial correlation: F-stat. = 0.01 [0.99] Normality test: χ2(2) = 0.20 [0.91] Heteroscedasticity: F-stat. = 1.82 [0.03] Sample period: 1975 Q1–1998 Q1 Single-equation dynamic responses: Response of consumers’ expenditure level to a 1% shock to RHS variables Per cent Quarters ahead Real labour Real net Real gross income financial wealth housing wealth 1 0.3 0.02 0.12 4 0.6 0.04 0.09 8 0.7 0.06 0.07 Long run (LR) 0.9 0.07 0.05 50% of LR by 3 quarters 3 quarters o/s 90% of LR by 11 quarters 12 quarters o/s Quarters ahead 1 4 8 Long run (LR) Per cent Nominal interest rate -0.003 -0.002 -0.0 0.0 Unemployment rate -0.07 -0.04 -0.02 0.0 Real interest rate 0.000 -0.001 -0.002 -0.003 6 quarters 15 quarters Real non-labour income 0.05 0.03 0.01 0.0 o/s = overshoots eventual long-run response in short term. 6.2.5 Fixed investment (I) Fixed investment is the sum of business investment, housing investment and government investment. It = IBUSt + IHt + IGt where (6.2.9) The macroeconometric model 31 I = fixed investment (6.2.9). IBUS = business investment (6.2.12). IH = private sector dwellings investment (6.2.13). IG = general government investment (exogenous), (see Section 6.2.9). 6.2.6 The capital stock (KNH, KBUSNH) The capital stock is the previous period’s stock (allowing for depreciation at the exogenous rate (1–BETA)) plus current investment. 21% of government investment is assumed to be housing, consistent with the average historical relationship. KNHt = BETANH.KNHt–1 + It – IHt – 0.21IGt (6.2.10) KBUSNHt = BETA.KBUSNHt–1 + IBUSt (6.2.11) where KNH = capital stock, excluding residential housing (6.2.10). KBUSNH = business non-residential capital stock (6.2.11). 1–BETANH = whole-economy net capital stock net of housing depreciation rate (exogenous). 1–BETA = business sector net capital stock depreciation rate (exogenous). IG = general government investment (exogenous), (see Section 6.2.9). IBUS = business investment (6.2.12). 6.2.7 Business investment (IBUS) The assumed Cobb-Douglas production technology implies that the capital-output ratio is a function of the user cost of capital with a unit coefficient in the long run. But adjustment is sluggish. ∆ibust = − 0.054 + 0.11 ∆ibust −1 + 0.19 ∆ibust − 2 + 0.18 ∆ibust − 3 (−1.9) (1.0) (1.7) (1.8) + 0.17 ∆ibust − 4 + 1.0 ∆gdpt −1 (1.7) (1.5) − 0.047 [3.09 + ibust −1 − kbusnht − 2 + 0.27 ( kbusnht − 2 − gdpt − 2 + rcct −1 )] (−1.9) + dummy where IBUS = business investment (6.2.12). GDP = GDP(A) at factor cost (6.2.1). KBUSNH = business non-residential capital stock (6.2.11). RCC = real cost of capital (6.1.5). DUMMY = 1985 Q2. (6.2.12) 32 Economic models at the Bank of England Adjusted R2: 0.36 Equation standard error: 0.028 LM test for serial correlation: F-stat. = 1.35 [0.27] Normality test: χ2(2) = 2.28 [0.32] Heteroscedasticity: F-stat. = 1.60 [0.10] Sample period: 1983 Q2–1999 Q3 Single-equation dynamic responses: Response of business investment level to a 1% shock to RHS variables Per cent Quarters ahead Real cost GDP output of capital 1 -0.01 1.0 4 -0.06 1.4 8 -0.01 1.6 Long run (LR) -0.27 0.27 The structure of the entire supply side of the MM (including capital accumulation (6.2.11) and the production function (6.3.11)) ensures that in the long run a 1% increase in the real cost of capital will result in a 1% decrease in the level of business investment and the capital-output ratio. 6.2.8 Private sector dwellings investment (IH) Private sector dwellings investment (IH) follows the growth of business investment. ∆iht = ∆ibust (6.2.13) where IH = private sector dwellings investment (6.2.13). IBUS = business investment (6.2.12). 6.2.9 Government investment (IG) In the simulations described in Section 5, real government investment (IG) is assumed to be exogenous. Nominal government investment (IGL) is derived by identity using the overall GDP deflator (6.4.1). But announced nominal government spending plans provide the basis for forecasting this component, with real spending defined by the inverse of equation (6.2.14) below. IGLt = IGt . PGDPt 6.2.10 (6.2.14) Government consumption (GL) In the simulation described in Section 5, real government consumption (G) is assumed to be exogenous. Nominal government consumption (GL) is derived by identity using the government The macroeconometric model 33 consumption deflator (PG) (6.4.14). But announced nominal government spending plans provide the basis for forecasting this component, with real spending then defined by the inverse of equation (6.2.15) below. GLt = Gt . PGt 6.2.11 (6.2.15) Stockbuilding (II) Net stockbuilding is defined as the change in total stocks. IIt = KIIt – KIIt–1 (6.2.16) where II = net stockbuilding (6.2.16). KII = stock level (6.2.17). In the medium term, the stock-output ratio follows a downward (time) trend. ∆kiit = 0.03 + 0.14 ∆gdpt −1 + 0.26 ∆gdpt − 2 − 0.13[kiit −1 − gdpt −1 + 0.004 TIMEt −1 ] (1.9) (1.2) (1.8) (6.2.17) (−2.5) where KII = stock level (6.2.17). GDP = GDP(A) at factor cost (6.2.1). TIME = time trend. Adjusted R2: 0.30 Equation standard error: 0.006 LM test for serial correlation: F-stat. = 2.15 [0.09] Normality test: χ2(2) = 1.07 [0.58] Heteroscedasticity: F-stat. = 1.05 [0.41] Sample period: 1982 Q1–1998 Q2 6.2.12 Export volumes of goods and services (X) Both of the trade volume equations are modelled as a function of relative prices and total demand for exports or imports (proxied by world trade (TRAD) (exogenous) and domestic demand (DD) (6.2.7) respectively). ∆xt = 0.72 − 0.33 ∆ xt −1 − 0.10 ∆ rxrxt + 0.30 ∆ tradt (2.9) (−2.8) (−1.3) (1.5) − 0.11 [ xt −1 − tradt −1 + 0.69rxrxt −1 ] + dummy (−2.9) (1.7) (6.2.18) 34 Economic models at the Bank of England where X = exports of goods and services (6.2.18). RXRX = exporters’ real exchange rate (6.1.9). TRAD = world trade (exogenous). DUMMY = 1991 Q1. Adjusted R2: 0.33 Equation standard error: 0.016 LM test for serial correlation: F-stat. = 1.35 [0.37] Normality test: χ2(2) = 1.95 [0.38] Heteroscedasticity: F-stat. = 0.51 [0.90] Sample period: 1985 Q3–1997 Q4 Single-equation dynamic responses: Response of export volume level to a 1% shock to RHS variables Per cent Quarters ahead Exporters’ real World trade exchange rate 1 -0.1 0.3 4 -0.3 0.5 8 -0.5 0.6 Long run (LR) -0.7 1.0 50% of LR by 7 quarters 5 quarters 90% of LR by 26 quarters 24 quarters 6.2.13 Import volumes of goods and services (M) ∆mt = − 0.25 + 1.73 ∆ddt − 0.21 [ mt −1 − ddt −1 + 0.22 rxrmt −1 − 0.90 SPECt −1 ] (−3.3) (8.3) (−3.3) (1.1) + dummy where M = imports of goods and services (6.2.19). DD = total domestic expenditure (6.2.7). RXRM = importers’ relative price (6.1.10). SPEC = trade specialisation term (exogenous). DUMMY = 1981 Q1. Adjusted R2: 0.64 Equation standard error: 0.018 LM test for serial correlation: F-stat. = 0.12 [0.95] Normality test: χ2(2) = 106.1 [0.0] (−5.6) (6.2.19) The macroeconometric model 35 Heteroscedasticity: F-stat. = 1.12 [0.36] Sample period: 1980 Q2–1997 Q4 Single-equation dynamic responses: Response of import volume level to a 1% shock to RHS variables Per cent Quarters ahead Importers’ relative Domestic demand Specialisation price 1 0.0 1.7 0.0 4 -0.1 1.3 0.5 8 -0.1 1.1 0.8 Long run (LR) -0.2 1.0 0.9 50% of LR by 3 quarters o/s 3 quarters 90% of LR by 10 quarters o/s 10 quarters o/s = overshoots eventual long-run response in short term. 6.2.14 Balance of payments (BAL, BALT, BIPD and BTRF) The current account balance (BAL) is determined by an accounting identity. It is the sum of the nominal trade balance (BALT), the balance of interest, dividends and profits (BIPD) and the balance of transfers (BTRF) (exogenous). BALt = BALTt + BIPDt + BTRFt (6.2.20) The nominal balance of trade is also defined by an accounting identity. BALt = Xt . PXt – Mt . PMt (6.2.21) where BALT = nominal balance of trade (6.2.21). X = exports of goods and services (6.2.18). M = imports of goods and services (6.2.19). PX = export price deflator (6.4.3). PM = import price deflator (6.4.2). The balance of interest payments, dividends and profits (BIPD) is proxied by the product of the exogenous world nominal interest rate (WRS) and the average net external assets (NEA) over the current and past quarter. WRSt NEAt + NEAt −1 BIPDt = 400 2 where (6.2.22) 36 Economic models at the Bank of England BPID = balance of interest, dividends and profits (6.2.22). WRS = world nominal interest rates (exogenous). NEA = net external assets (6.2.23). 6.2.15 Net external assets (NEA) Net external assets are defined as the difference between gross UK holdings of foreign assets (UKA) (6.2.24) and foreign holdings of UK assets (FOH) (6.2.25). NEAt = UKAt – FOHt (6.2.23) Both gross UK and foreign asset holdings are modelled using a simple stock/flow framework. The current account balance (assumed equal to the capital account balance) gives the flow apportioned to the two stocks according to their average ratio across the 1990s. WPXt WPXt −1 UKAt = 0.51BALt + UKAt −1 EERt EERt −1 (6.2.24) where UKA = UK holdings of foreign assets (6.2.24). BAL = current account balance (6.2.20). WPX = world export prices (exogenous). EER = sterling effective exchange rate index (6.1.6). PGDPt FOHt = − 0.49 BALt + FOHt −1 PGDPt −1 (6.2.25) where FOH = foreign holdings of UK assets (6.2.25). BAL = current account balance (6.2.20). PGDP = GDP deflator at factor cost (6.4.1). 6.3 6.3.1 Labour market Average earnings (EARN) The labour market earnings equation is based on a forward-looking model of contract dynamics. The desired or target wage (W*) is defined as: wt* = pgdpt + gdpt – empt – remt – 0.013 URt + ZPROXY where PGDP = GDP deflator at factor cost (6.4.1). UR = rate of unemployment (6.3.8). (6.3.1) The macroeconometric model 37 ZPROXY = measure of structural effects of labour market developments (exogenous). GDP = GDP(A) at factor cost (6.2.1). EMP = level of employment in heads (6.3.12). REM = effective employers’ social contribution tax rate (exogenous). ZPROXY is designed to capture movements in unobservable structural variables that affect the labour market (such as union power and the replacement ratio), and is derived by fitting a Hodrick-Prescott filter through data on the labour share of income and the unemployment rate. Following Moghadam and Wren-Lewis (1994), the pure theoretical model of contract dynamics sets earnings each period equal to a backward and a forward convolution of expected wages, wstarc, where: wstarct = (1 / 16)( w∗t ,t + w∗t ,t +1 + w∗t ,t + 2 + w∗t ,t + 3 + w∗t −1,t −1 + w∗t −1,t + w∗t −1,t +1 + w∗t −1,t + 2 + w∗t − 2,t − 2 + w∗t − 2,t −1 + w∗t − 2,t + w∗t − 2,t +1 (6.3.2) + w∗t − 3,t − 3 + w∗t − 3,t − 2 + w∗t − 3,t −1 + w∗t − 3,t ), and w*i,j is the expectation of w*j formed at time i. In estimation, these forward-looking terms are treated as rational. The estimated equation also embodies the assumption that wage-setters partly adopt a rule of thumb in setting their contracts (using a combination of lagged wage growth and current growth of retail prices and productivity to determine their wage settlements) in addition to explicitly forward-looking considerations. earnt = 0.79 {0.63(0.25)[(earnt −1 + earnt − 2 + earnt − 3+ earnt − 4 ) (26.7) (6.0) + (2.5) 0.65 ( ∆earnt −1 + ∆earnt − 2 + ∆earnt − 3 + ∆earnt − 4 ) (10.1) + (2.5) (1 − 0.65)( ∆rpt + ∆rpt −1 + ∆rpt − 2 + ∆rpt − 3 )] + (1 − 0.63)[earnt −1 + 0.65∆earnt −1 + (1 − 0.65)∆rpt ]} + (1 − 0.79)wstarc t where EARN = average earnings index (6.3.3). RP = RPIX plus productivity (6.3.4). Adjusted R2: 0.99 Equation standard error: 0.005 LM test for serial correlation: F-stat. = 0.71 [0.586] Normality test: χ2(2) = 0.58 [0.747] Heteroscedasticity: F-stat. = 6.17 [0.016] Sample period: 1980 Q4–1997 Q4 (6.3.3) 38 Economic models at the Bank of England rpt = rpixt + gdpt – empt (6.3.4) where RP = RPIX inflation adjusted by productivity (6.3.4). RPIX = RPI excluding mortgage interest payments (6.4.6). GDP = GDP(A) at factor cost (6.2.1). EMP = level of employment in heads (6.3.12). In simulations, expected future values of w* (where w*ij is the expectation of w*j formed at time i) can be treated in different ways. Either as a model-consistent expectation. w*t,t+1 = w*t+1 ; w*t,t+2 = w*t+2 ; w*t,t+3 = w*t+3 (6.3.5) Or as the result of a backward-looking rule, as adopted in the simulations. w∗t ,t + m = pgdpt + gdpt − empt − remt − 0.013URt + ZPROXYt m . INFEt + log1 + 400 (GDPt / EMPt ) − (GDPt − 4 / EMPt − 4 ) + log1 + m 4 (GDPt − 4 / EMPt − 4 ) (6.3.6) for m = 1, 2 and 3. Single-equation dynamic responses: Response of the level of earnings to a 1% shock to RHS variables Per cent Quarters ahead GDP deflator Productivity Unemployment 1 0.2 0.5 -0.2 4 0.6 1.1 -0.7 8 0.9 1.2 -1.2 Long run (LR) 1.0 1.0 -1.3 50% of LR by 4 quarters o/s 4 quarters 90% of LR by 8 quarters o/s 8 quarters o/s = overshoots eventual long-run response in short term. 6.3.2 Unemployment level, unemployment rate, participation rate (UN, UR, PA) The level of unemployment (UN) is modelled as an identity, relating unemployment to changes in employment (EMP), the population aged 16 and over (POP) (exogenous) and the participation rate (PA). UNt = PAt . POPt – EMPt (6.3.7) The macroeconometric model 39 where UN = level of unemployment (6.3.7). PA = participation rate (6.3.9). POP = population aged 16 and over (exogenous). EMP = level of employment in heads (6.3.12). The rate of unemployment (UR) is an identity. UNt URt = 100 EMPt + UNt (6.3.8) where UR = rate of unemployment (6.3.8). UN = level of unemployment (6.3.7). EMP = level of employment in heads (6.3.12). and the participation rate is given by: POWA POWA PA = 1 − INWA − INOLD 1 − POP POP (6.3.9) where PA = participation rate (6.3.9). INWA = proportion of population of working age that is inactive (6.3.10). POWA = population of working age (exogenous). POP = population aged 16 and over (exogenous). INOLD = proportion of population over retirement age that is inactive (exogenous). INWA can be assumed invariant to the economy cycle or modelled by a simple cyclical influence derived from lagged employment (as a proportion of the working-age population). The latter assumption was used in the simulations described in Section 5. EMPt −1 EMPt − 2 INWAt = 0.06 − 0.25 + 0.20 + 0.00006TIME + 0.87 INWAt −1 POWAt −1 POWAt − 2 (6.3.10) (2.3) (−5.6) (4.2) (2.9) (16.6) where INWA = proportion of population of working age that is inactive (6.3.10). EMP = level of employment in heads (6.3.12). POWA = population of working age (exogenous). TIME = time trend. 40 Economic models at the Bank of England Adjusted R2: 0.98 Equation standard error: 0.001 Sample period: 1984 Q1–1998 Q4 6.3.3 Employment in hours (EMPH) Long-run employment in hours is derived from an inverted production function. Changes in GDP appear in the dynamic hours equation. ∆empht = − 0.0008 + 0.43∆empht −1 + 0.28∆gdpt + 0.17[CAPUt −1 ] (−1.3) (4.9) (4.3) (4.6) (6.3.11) where EMPH = total employment in hours (6.3.11). GDP = GDP(A) at factor cost (6.2.1). CAPU = capacity utilisation (6.2.6). Adjusted R2: 0.76 Equation standard error: 0.004 LM test for serial correlation: F-stat. = 0.35 [0.846] Normality test: χ2(2) = 1.61 [0.445] Heteroscedasticity: F-stat. = 0.10 [0.753] Sample period: 1980 Q1–1998 Q1 Single-equation dynamic responses for equation: Response of employment in hours level to a 1% shock to RHS variables Per cent Quarters ahead GDP output Capital stock 1 0.3 0.0 4 0.9 -0.2 8 1.3 -0.4 Long run (LR) 1.4 -0.4 50% of LR by 3 quarters 5 quarters 90% of LR by 7 quarters 10 quarters 6.3.4 Employment in heads (EMP) Employment in heads (EMP) can be written as: EMPt = EMPHt AVH t where EMP = level of employment in heads (6.3.12). EMPH = total employment in hours (6.3.11). (6.3.12) The macroeconometric model 41 AVH = average hours per worker (6.3.13). 6.3.5 Average hours per worker (AVH) Average hours per worker is a decreasing function of the extent of part-time working, and is cyclical about a long-run trend. ∆avht = − 0.21 − 0.06 avht −1 + 0.32 ∆avht −1 (−2.4) (−2.4) (3.0) − 0.61( ∆PTSHt − 0.32 ∆PTSHt −1 + 0.06 PTSHt −1 ) + 0.09CAPUt −1 (6.3.13) (3.2) where AVH = average hours per worker (6.3.13). PTSH = part-time share of employment (exogenous). CAPU = capacity utilisation (6.2.6). Adjusted R2: 0.30 Equation standard error: 0.004 LM test for serial correlation: F-stat. = 0.86 [0.49] Normality test: χ2(2) = 0.27 [0.87] Heteroscedasticity: F-stat. = 4.75 [0.033] Sample period: 1980 Q1–1998 Q1 Single-equation dynamic responses for equation: Response of average hours level to a 1% shock to RHS variables Per cent Quarters ahead Part time share Capacity utilisation 1 -0.6 0.0 4 -0.6 0.3 8 -0.6 0.7 Long run (LR) -0.6 1.4 50% of LR by 1 quarter 9 quarters 90% of LR by 1 quarter 25 quarters 6.3.6 Unit labour costs (ULC) Nominal unit labour costs (ULC) are defined by the following identity: ULCt = EARNt . REMt . EMPt GDPt where ULC = nominal unit labour costs (6.3.14). (6.3.14) 42 Economic models at the Bank of England EARN = average earnings index (6.3.3). REM = effective employers’ social contribution tax rate (exogenous). EMP = level of employment in heads (6.3.12). GDP = GDP(A) at factor cost (6.2.1). 6.4 6.4.1 Prices Domestic output prices—the GDP deflator (PGDP) The PGDP equation is modelled as a long-run mark-up over unit labour costs. Short-run movements in the mark-up are captured by the capacity utilisation term. ∆pgdpt = − 0.19 + 0.24 ∆pgdpt −1 + 0.48∆ulct −1 + 0.27∆ulct − 2 + 0.25CAPUt −1 (−0.7) (1.9) (4.0) − 0.07[ pgdpt −1 − ulct −1 ] (2.7) (6.4.1a) (−1.1) where PGDP = GDP deflator at factor cost (6.4.1). ULC = nominal unit labour costs (6.3.14). CAPU = capacity utilisation (6.2.6). Adjusted R2: 0.24 Equation standard error: 0.012 LM test for serial correlation: F-stat. = 1.02 [0.36] Normality test: χ2(2) = 0.11 [0.94] Heteroscedasticity: F-stat. = 3.37 [0.001] Sample period: 1975 Q2–1997 Q1 Single-equation dynamic responses: Response of GDP deflator level to a 1% shock to RHS variables Per cent Quarters ahead Unit labour costs Capacity utilisation 1 0.0 0.0 4 1.1 0.8 8 1.1 1.8 Long run (LR) 1.0 0.0 50% of LR by o/s o/s 90% of LR by o/s o/s o/s = overshoots eventual long-run response in short term. An alternative, used to account for possible terms-of-trade effects in recent years, includes import prices. The macroeconometric model 43 ∆pgdpt = − 0.27 + 0.56 ∆ulct −1 + 0.19 ∆ulct − 2 + 0.26 ∆pmt −1 + 0.18CAPUt −1 (5.4) (5.7) (2.3) − 0.09 [ pgdpt −1 − ulct −1 ] (6.4.1b) (−1.5) where PGDP = GDP deflator at factor cost (6.4.1). CAPU = capacity utilisation (6.2.6). ULC = nominal unit labour costs (6.3.14). PM = import price deflator (6.4.2). Adjusted R2: 0.40 Equation standard error: 0.0088 LM test for serial correlation: F-stat. = 0.25 [0.77] Normality test: χ2(2) = 0.95 [0.62] Heteroscedasticity: F-stat. = 1.20 [0.31] Sample period: 1980 Q1–1997 Q1 6.4.2 Goods and services import deflator (PM) In the short run import prices are affected by unit labour costs, non-oil commodity prices, oil prices and M6 export prices. In the long run, import prices are determined by non-oil commodity prices, oil prices and M6 export prices. ∆pmt = − 0.07 + 0.08∆(comnust −1 − edst −1 ) + 0.48∆( wpxt − eert ) (−3.1) (3.3) (10.5) + 0.03∆( petspott − edst ) + 0.41∆ulct −1 (2.9) − 0.18[ pmt −1 − 0.93 ( wpxt −1 − eert −1 ) − 0.04 ( petspott −1 − edst −1 ) (−3.1) − 0.03 (comnust −1 − edst −1 )] where PM = import price deflator (6.4.2). COMNUS = world non-oil commodity prices (index, US$) (exogenous). EDS = US dollar-sterling exchange rate (6.1.8). EER = sterling effective exchange rate index (6.1.6). PETSPOT = oil spot prices (US$) (exogenous). ULC = nominal unit labour costs (6.3.14). WPX = world export prices (exogenous). Adjusted R2: 0.69 Equation standard error: 0.012 (6.4.2a) 44 Economic models at the Bank of England LM test for serial correlation: F-stat. = 0.29 [0.75] Normality test: χ2(2) = 6.22 [0.07] Heteroscedasticity: F-stat. = 0.98 [0.53] Sample period: 1984 Q1–1997 Q4 Single-equation dynamic responses: Response of import price level to a 1% shock to RHS variables Per cent Quarters ahead Sterling M6 Sterling non-oil Sterling oil export prices commodity prices prices 1 0.5 0.08 0.03 4 0.7 0.06 0.03 8 0.8 0.04 0.04 Long run 0.9 0.03 0.04 50% of LR by 1 quarter o/s 1 quarter 90% of LR by 9 quarters o/s 6 quarters Unit labour costs 0.4 0.2 0.1 0.0 o/s = overshoots eventual long-run response in short term. An alternative specification sometimes used in forecasting includes an additional dynamic term for the dollar-sterling exchange rate and relaxes the dynamic homogeneity constraint. ∆pmt = − 0.07 + 0.02 ∆(comnust −1 − edst −1 ) + 0.95∆wpxt − 0.28∆eert (−4.3) (1.6) (3.9) (5.7) + 0.02 ∆( petspott − edst ) − 0.14 ∆edst (1.8) ( −4.0) − 0.19 [ pmt −1 − 0.93 ( wpxt −1 − eert −1 ) − 0.04 ( petspott −1 − edst −1 ) ( −4.5) − 0.03 (comnust −1 − edst −1 )] where PM = import price deflator (6.4.2). COMNUS = world non-oil commodity prices (index, US$) (exogenous). EDS = Sterling-US dollar exchange rate (6.1.8). EER = sterling effective exchange rate index (6.1.6). PETSPOT = oil spot prices (US$) (exogenous). ULC = nominal unit labour costs (6.3.14). WPX = world export prices (exogenous). Adjusted R2: 0.83 Equation standard error: 0.009 LM test for serial correlation: F-stat. = 0.84 [0.50] Normality test: χ2(2) = 4.9 [0.09] (6.4.2b) The macroeconometric model 45 Heteroscedasticity: F-stat. = 1.22 [0.28] Sample period: 1984 Q1–1997 Q4 6.4.3 Goods and services export deflator (in sterling) (PX) Export prices are modelled as a function of M6 export prices in sterling terms, UK unit labour costs and oil prices. ∆pxt = − 0.46 + 0.30 ∆( wpxt − eert ) + 0.67∆ulct + 0.03∆( petspott − edst ) ( −5.8) (13.9) (3.0) [ ] − 0.33 pxt −1 − 0.55 ( wpxt −1 − eert −1 ) − 0.40 ulct −1 − 0.05 ( petspott −1 − edst −1 ) (6.4.3) ( −5.9) ( −11.2) + dummy where PX = export price deflator (6.4.3). WPX = world export prices (exogenous). EER = sterling effective exchange rate index (6.1.6). ULC = nominal unit labour costs (6.3.14). PETSPOT = oil spot prices (US$) (exogenous). EDS = US dollar-sterling exchange rate (6.1.8). DUMMY = 1989 Q2. Adjusted R2: 0.58 Equation standard error: 0.012 LM test for serial correlation: F-stat. = 0.33 [0.72] Normality test: χ2(2) = 0.03 [0.99] Heteroscedasticity: F-stat. = 2.03 [0.04] Sample period: 1985 Q3–1997 Q4 Single-equation dynamic responses: Response of export price level to a 1% shock to RHS variables Per cent Quarters ahead Unit labour costs Oil prices Sterling M6 export prices 1 0.7 0.03 0.3 4 0.5 0.04 0.5 8 0.4 0.05 0.5 Long run (LR) 0.4 0.05 0.6 50% of LR by o/s 1 quarter 1 quarter 90% of LR by o/s 5 quarters 5 quarters o/s = overshoots eventual long-run response in short term. 46 6.4.4 Economic models at the Bank of England Domestic price index (DPP) An index for the price of domestic output produced and consumed in the United Kingdom is constructed by removing export prices from the GDP deflator. dppt = pgdpt – 0.20 pxt (6.4.4) where DPP = domestic price index (6.4.4). PGDP = GDP deflator at factor cost (6.4.1). PX = export price deflator (6.4.3). 6.4.5 RPIY RPIY is a weighted combination of the domestic price index and import prices. ∆rpiyt = 0.68 + 0.41 ∆( dppt ) + 0.33 ∆( dppt −1 ) + 0.21 ∆( dppt − 2 ) (0.7) (4.8) (4.1) (2.6) + 0.14 ∆pmt + 0.07 ∆pmt −1 + 0.04 ∆pmt − 2 (4.1) (1.9) − 0.14 [rpiyt −1 − 1.0 dppt −1 − 0.20 pmt −1 ] ( −2.3) + seasonal dummies where RPIY = RPI excluding MIPS and indirect taxes (6.4.5). PM = import price deflator (6.4.2). DPP = domestic price index (6.4.4). Adjusted R2: 0.85 Equation standard error: 0.003 LM test for serial correlation: F-stat. = 3.00 [0.07] Normality test: χ2(2) = 0.26 [0.87] Heteroscedasticity: F-stat. = 0.59 [0.86] Sample period: 1987 Q1–1997 Q1 (6.4.5a) The macroeconometric model 47 Single-equation dynamic responses: Response of RPIY level to a 1% shock to RHS variables Per cent Quarters ahead Import prices Domestic prices 1 0.1 0.4 4 0.2 1.1 8 0.2 1.0 Long run (LR) 0.2 1.0 50% of LR by 1 quarter 2 quarter 90% of LR by 2 quarter o/s o/s = overshoots eventual long-run response in short term. An alternative specification used for some simulations models RPIY as a function of import prices and unit labour costs: ∆rpiyt = 0.11 + 0.62 ∆(rpiyt −1 ) + 0.30 ∆(remt + earnt ) + 0.07∆( pmt ) (2.1) (8.8) (4.4) + 0.04 CAPUt −1 − 0.04 [rpiyt −1 − 0.20 pmt −1 − 0.8 ulct −1 ] (1.4) (6.4.5b) ( −2.0) + seasonal dummies where RPIY = RPI excluding MIPS and indirect taxes (6.4.5). REM = effective employers’ social contribution tax rate (exogenous). EARN = average earnings index (6.3.3). PM = import price deflator (6.4.2). CAPU = capacity utilisation (6.2.6). ULC = nominal unit labour costs (6.3.14). Adjusted R2: 0.82 Equation standard error: 0.003 LM test for serial correlation: F-stat. = 6.50 [0.01] Normality test: χ2(2) = 0.71 [0.70] Heteroscedasticity: F-stat. = 1.17 [0.32] Sample period: 1982 Q2–1999 Q1 6.4.6 RPIX RPIX is constructed in two stages. First, indirect taxes are added to RPIY to calculate RPIX excluding council taxes (RPXC). Then council taxes are added to give RPIX itself. None of the equations is behavioural, so any wedge between RPIY and RPIX inflation rates is driven solely by assumptions about indirect taxes and council tax. Throughout, price changes are calculated relative to the first quarter of the year, a feature designed to approximate chain-linking. 48 Economic models at the Bank of England RPIX is calculated as a weighted average of RPXC (6.4.7) and RPCC (6.4.10). RPIX = (Q1. RPIXt − 4 + Q2. RPIXt −1 + Q3. RPIXt − 2 + Q4. RPIXt − 3 ). WCC RPCC 1 − WMIP . Q1. RPCC + Q2. RPCC + Q3. RPCC + Q4. RPCC + (6.4.6) t −4 t −1 t −2 t −3 WCC RPXC 1 − . 1 − WMIP Q1. RPXCt − 4 + Q2. RPXCt −1 + Q3. RPXCt − 2 + Q4. RPXCt − 3 where RPIX = RPI excluding mortgage interest payments (6.4.6). RPCC = council tax and rates sub-index of RPI (6.4.10). RPXC = RPI excluding MIPS and council taxation (6.4.7). WCC = weight of council tax and rates in RPI per 1,000 (exogenous). WMIP = weight of MIPS in RPI per 1,000 (exogenous). 6.4.6.1 Indirect taxes The retail price index excluding the mortgage interest payment sub-index, local authorities and indirect taxes (RPIY) omits two types of indirect taxation, value-added tax and excise duties, both of which are added to calculate RPXC. RPXC is modelled as a weighted sum of changes in an index of excise duties (DUTY) and RPIY, scaled to allow for the effects of changes in VAT. RPXC = VAR . (Q1. RPXCt − 4 + Q2. RPXCt −1 + Q3. RPXCt − 2 + Q4. RPXCt − 3 ). WDUT DUTY WDUT + WRPY Q1. DUTY + Q2. DUTY + Q3. DUTY + Q4. DUTY t −4 t −1 t −2 t − 3 (6.4.7) WDUT RPIY + 1 − WDUT + WRPY Q1. RPIYt − 4 + Q2. RPIYt −1 + Q3. RPIYt − 2 + Q4. RPIYt − 3 where RPXC = RPI excluding MIPS and council taxation (6.4.7). DUTY = index of duty element of RPI (6.4.9). RPIY = RPI excluding MIPS and indirect taxes (6.4.5). WDUT = weight of duty element in RPI (exogenous). WRPY = weight of RPIY in RPI (exogenous). The VAT multiplier (VAR) is a weighted sum of changes to the value-added taxation rates, where the weights reflect the proportion of the RPIX basket covered by VAT at each rate. The macroeconometric model 49 1 + RVAT / 100 VAR = 0.40 + 0.54 Q 1 1 + RVAT / 100 Q 2 1 RVAT / 100 Q 3 1 RVAT / 100 Q 4 1 RVAT / 100 + + + + + + ( ) ( ) ( ) ( ) t −4 t −1 t −2 t −3 1 + FVAT / 100 + 0.04 Q 1 1 FVAT / 100 Q 2 1 FVAT / 100 Q + + + + 3 1 + FVAT / 100 + Q 4 1 + FVAT / 100 ( ) ( ) ( ) ( ) t −2 t −3 t −4 t −1 (6.4.8) 1 + IVAT / 100 + 0.02 Q 1 1 IVAT / 100 Q 2 1 IVAT / 100 Q 3 1 IVAT / 100 Q 4 1 IVAT / 100 + + + + + + + ( ) ( ) ( ) ( ) t −4 t −1 t −2 t −3 where VAR = the VAT multiplier (6.4.8). RVAT = standard rate of VAT (exogenous). FVAT = rate of VAT charged on domestic fuel and light (exogenous). IVAT = rate of VAT charged on insurance (exogenous). Excise duties (DUTY) are indexed to the RPI, changing in the first quarter of each year, in line with the prevailing four-quarter RPI inflation rate. DUTY = (1 – Q1) DUTYt–1 + Q1 . DUTYt–1 . (RPIt / RPIt–4) (6.4.9) where DUTY = index of duty element of RPI (6.4.9). RPIY = RPI excluding MIPS and indirect taxes (6.4.5). 6.4.6.2 Council tax The council tax component of the RPI (RPCC) is held flat except for in Q2, when council taxes are set. Council taxes are indexed to RPXC, and so rise by the four-quarter growth rate of RPXC prevailing in Q2 of each year. RPCCt = (1 – Q2) RPCCt–1 + Q2 . RPCCt–1 . (RPXCt / RPXCt–4) (6.4.10) where RPCC = council tax and rates sub-index of RPI (6.4.10). RPXC = RPI excluding MIPS and council taxation (6.4.7). 6.4.7 RPI The RPI is calculated as a weighted average of RPIX (6.4.6) and the index of mortgage interest payments (MIPS) (6.4.12). As with RPIX, price changes are calculated relative to the first quarter of the year, a feature designed to approximate chain-linking. 50 Economic models at the Bank of England RPI = (Q1. RPIt − 4 + Q2. RPIt −1 + Q3. RPIt − 2 + Q4. RPIt − 3 ). MIPS WMIP + Q1. MIPSt − 4 + Q2. MIPSt −1 + Q3. MIPSt − 2 + Q4. MIPSt − 3 RPIX (1 − WMIP ) Q1. RPIXt − 4 + Q2. RPIXt −1 + Q3. RPIXt − 2 + Q4. RPIXt − 3 (6.4.11) where RPI = retail price index (6.4.11). MIPS = mortgage interest payments sub-index of RPI (6.4.12). RPIX = RPI excluding mortgage interest payments (6.4.6). WMIP = weight of MIPS in RPI (exogenous). The ONS calculates MIPS from the average debt outstanding on mortgages. The debt was previously subdivided between that eligible for tax relief and the rest. Around 75% was eligible for tax relief, hence the multiplier attached to RMI. Since the removal of mortgage interest relief in April 2000, RMI has been set to zero. We model MIPS as a function of gross housing wealth, the mortgage interest rate and the average rate at which mortgage interest relief was claimed (RMI) (exogenous). GHW is used as a proxy for the stock of nominal housing debt. RMM4t RMIt GHWt 1 − 0.75 100 100 MIPSt = 64005.36 (6.4.12) where MIPS = mortgage interest payments sub-index of RPI (6.4.12). GHW = gross housing wealth (6.1.13). RMM4 = mortgage interest rate (6.1.3). RMI = average rate at which MIRAS was claimed (exogenous). 6.4.8 The consumers’ expenditure deflator (PC) The consumers’ expenditure deflator (PC) is derived from RPXC (retail price index excluding MIPS and council tax), because council tax payments are not counted as part of consumption. The expenditure deflator is seasonally adjusted by applying quarterly dummies to RPXC. This is necessary because national accounts data are seasonally adjusted, but retail prices data are not. The constant is imposed to correct for differences in indexation between the two series. pct = rpxct – 5.01 + seasonal dummies where PC = total final consumers’ expenditure deflator (6.4.13). RPXC = RPI excluding MIPS and council taxation (6.4.7). (6.4.13) The macroeconometric model 6.4.9 51 Government consumption deflator (PG) The government expenditure deflator is proxied by movements in unit labour costs and the retail price index excluding council taxation payments. The weights reflect the fact that the breakdown of government consumption is roughly half on goods and half on services. pgt = – 4.0 + 0.5rpxct + 0.5ulct (6.4.14) where PG = government expenditure deflator (6.4.14). RPXC = RPI excluding MIPS and council taxation (6.4.7). ULC = nominal unit labour costs (6.3.14). 6.4.10 House prices (PHSE) House prices are determined by average earnings and the long real rate in the long run, while GDP enters the dynamics (in addition to earnings). ∆phset = − 0.01 + 0.35 ∆( phset −1 ) + 0.92 ∆(earnt ) + 0.92 ∆( gdpmt − 2 ) ( −0.8) (3.5) (2.2) (2.6) − 0.034 [ phset −1 − earnt −1 + 0.17 RLRt −1 ] + dummy ( −2.0) (1.2) where PHSE = UK house prices (6.4.15). EARN = average earnings index (6.3.3). GDPM = GDP(A) at market prices (6.2.3). RLR = 10-year index-linked bond yields (exogenous). DUMMY = 1998 Q3. Adjusted R2: 0.53 Equation standard error: 0.018 LM test for serial correlation: F-stat. = 4.43 [0.02] Normality test: χ2(2) = 1.27 [0.53] Heteroscedasticity: F-stat. = 1.03 [0.43] Sample period: 1982 Q2–1998 Q4 (6.4.15a) 52 Economic models at the Bank of England Single-equation dynamic responses: Response of house price level to a 1% shock to RHS variables Per cent Quarters ahead Earnings GDP Real interest rates 1 1.2 0.0 -0.01 4 1.4 1.3 -0.03 8 1.3 1.1 -0.06 Long run (LR) 1.0 0.0 -0.17 50% of LR by o/s o/s 13 quarters 90% of LR by o/s o/s 42 quarters o/s = overshoots eventual long-run response in short term. An alternative specification that imposes dynamic homogeneity is used in the simulations described in Section 5. ∆phset = − 0.01 + 0.28 ∆( phset −1 ) + 0.72 ∆(earnt ) + 0.92 ∆( gdpmt − 2 ) − 0.034 [ phset −1 − earnt −1 + 0.17 RLRt −1 ] + dummy (6.4.15b) where PHSE = UK house prices (6.4.15). EARN = average earnings index (6.3.3). GDPM = GDP(A) at market prices (6.2.3). RLR = 10-year index-linked bond yields (exogenous). DUMMY = 1998 Q3. A further alternative specification for the house price equation includes a measure of real user cost of housing. The user cost of housing is calculated using the short-term mortgage interest rate, adjusted for tax changes, offset by expected capital gains and allowing for other costs such as depreciation. Over the estimation period expected capital gains were proxied by past house price inflation. ∆phset = − 0.17 + 1.22 ∆(earnt ) + 0.56 ∆( gdpmt − 2 ) + 0.004 ∆ (nfwt −1 − pct −1 ) ( −2.5) (4.1) (2.0) (4.9) − 0.002 ∆(USERt −1 ) − 0.038 [ phset −1 − earnt −1 + 0.03USERt −1 ] + dummy ( −4.0) ( −2.6) where PHSE = UK house prices (6.4.15). EARN = average earnings index (6.3.3). GDPM = GDP(A) at market prices (6.2.3). ( −5.6) (6.4.15c) The macroeconometric model 53 NFW = net financial wealth (6.1.14). PC = total final consumers’ expenditure deflator (6.4.13). USER = real user cost of housing (exogenous). DUMMY = 1998 Q3. Adjusted R2: 0.65 Equation standard error: 0.015 LM test for serial correlation: F-stat. = 1.37 [0.26] Normality test: χ2(2) = 3.25 [0.20] Heteroscedasticity: F-stat. = 0.57 [0.86] Sample period: 1982 Q2–1998 Q4 6.4.11 Four-quarter RPIX inflation expectations (INFE) There are several possible options available within the model for inflation expectations formulation. Inflation expectations can be modelled as a simple autoregressive model, estimated using a ten-year rolling regression. The rolling-regression estimation is designed to capture an element of learning by agents. The model is generally re-estimated before each forecast, in order to reflect recent inflation experience. INFEt = 1.1 + 1.2 INFt −1 − 0.6 INFt − 2 (1.0) (9.7) (−3.2) (6.4.16a) where INFE = expectations of annual RPIX inflation (6.4.16). INF = four-quarter inflation rate RPIX. A second version of INFE is designed to be flexible, with both a backward and a forward-looking element. The Government inflation target (ZPSTA) may also affect expectations directly. INFEt = Z1INFt −1 + Z2 INFt + Z3 INFt + 4 + (1 − Z1 − Z2 − Z3 ) ZPSTA (6.4.16b) where INFE = expectations of annual RPIX inflation (6.4.16). INF = four-quarter inflation rate of RPIX. ZPSTA = Government inflation target (exogenous). The weights (Z1, Z2 and Z3) can be varied. Purely adaptive expectations are generated with Z1=1, Z2=Z3 = 0. Reducing Z1, Z2 and Z3 raises the weight attached to the inflation target. In the simulations described in Section 5, a simple (perfect foresight) variant is used: Z1=0, Z2=1, Z3=0. 54 6.5 Economic models at the Bank of England Fiscal policy The fiscal sector of the model has few estimated equations—it mainly comprises accounting identities and adding-up constraints. Taxation receipts are usually calculated from exogenous taxation rates and the relevant tax bases. 6.5.1 Taxation receipts Total taxation receipts (TAX) (6.5.1) are an accounting identity. They are equal to the sum of tax deductions from household income (TJL) (6.5.2); corporate income taxation receipts (TYC) (6.5.6); indirect taxes less subsidies within the United Kingdom (FCAL) (6.5.7); subsidies from the European Union (SBEU) (exogenous) less indirect taxes to the European Union (TXEU) (exogenous). TAXt = TJLt + TYCt + FCALt + SBEUt – TXEUt 6.5.2. (6.5.1) Tax deductions from household income Total tax deductions from household income (TJL) (6.5.2) are defined by an accounting identity. They are equal to the sum of receipts from taxes on household income (TYJ) (6.5.3); net social contributions from household sector (YJC) (6.5.4); and other current taxes paid by households (TCC) (6.5.5). TJLt = TYJt + YJCt + TCCt (6.5.2) Taxes on household income (TYJ) (6.5.3) are the product of the exogenous household income taxation rate (RJY) and wages, salaries and self-employed income (YE) (6.6.2). TYJt = RJYt . YEt (6.5.3) Net social contributions from the household sector (YJC) (6.5.4) are the product of the exogenous household sector social contribution rate (RJC) and wages, salaries and self-employed income (YE) (6.6.2). YJCt = RJCt . YEt (6.5.4) Other current taxes paid by households (TCC) (6.5.5) are estimated as a function of previous receipts, the council tax component of the RPI (RPCC) (6.4.10) and a time trend (TIME). tcct = 0.48 + 0.74tcct −1 + 1.23∆rpcct + 0.26rpcct −1 + 0.002TIMEt (1.7) 6.5.3 (19.6) (1.5) (6.5.5) (1.5) Taxes on corporate income Corporate income taxation receipts (TYC) (6.5.6) are calculated by the product of the exogenous corporate income taxation rate (RC) and nominal GDP (GDPL) (6.2.4). The macroeconometric model TYCt = RCt . GDPLt 6.5.4 55 (6.5.6) Indirect taxes less subsidies The nominal factor cost adjustment (FCAL) (6.5.7) is given by total taxes on production and imports (TE) (6.5.8) less government subsidies on products (SUBS) (6.5.11). FCALt = TEt – SUBSt 6.5.5 (6.5.7) Taxes on expenditure Total taxes on production and imports (TE) (6.5.8) are the sum of value-added taxation receipts (TVAT) (6.5.9) and other expenditure taxation receipts (TSD) (6.5.10). TEt = TVATt + TSDt (6.5.8) Value-added taxation receipts (TVAT) are calculated by the product of the exogenous value-added taxation rate (EVAT) and nominal consumption. TVATt = EVATt . Ct . PCt (6.5.9) where TVAT = value-added taxation receipts (6.5.9). EVAT = value-added taxation rate (exogenous). C = consumers’ expenditure (6.2.8). PC = total final consumers’ expenditure deflator (1995 = 1) (6.4.13). Other expenditure taxation receipts (TSD) are calculated by the product of the exogenous other expenditure taxation rate (RSD) and nominal consumption. TSDt = RSDt . Ct . PCt (6.5.10) where TSD = other expenditure taxation receipts (6.5.10). RSD = other expenditure taxation rate (exogenous). C = consumers’ expenditure (6.2.8). PC = total final consumers’ expenditure deflator (6.4.13). 6.5.6 Government subsidies Government subsidies on products (SUBS) (6.5.11) are calculated as the product of nominal GDP (GDPL) (6.2.4) and the exogenous effective government subsidies rate (RTS). SUBSt = RTSt . GDPLt (6.5.11) 56 6.5.7 Economic models at the Bank of England Other government expenditure Real government consumption (G) and investment (IG) are assumed exogenous in the simulations outlined in Section 5 (see Sections (6.1.9) and (6.1.10)). In addition to these national accounting concepts, nominal government expenditure includes current grants to the household sector (YJG)—predominantly social security payments—and interest payments on general government debt (DI). Nominal current grants are assumed to be uprated in line with the total final consumers’ expenditure deflator (PC) (6.4.13). ∆yjgt = ∆pct (6.5.12) Interest payments on government debt are modelled as a default, assuming 95% bond finance. RL ∆DIt = 0.95 t PSNBt 400 (6.5.13) where DI = general government debt interest payments (6.5.13). RL = 20-year bond yield (6.1.2). PSNB = public sector net borrowing (6.5.14). 6.5.8 Public sector net borrowing (PSNB) The PSNB is defined as the sum of the nominal expenditure components less taxation receipts. PSNBt = GLt + IGLt + YJGt + DIt – TAXt (6.5.14) where PSNB = public sector net borrowing (6.5.14). GL = nominal general government final consumption expenditure (6.2.15). IGL = nominal general government investment (6.2.14). YJG = current grants to the household sector (6.5.12). DI = general government debt interest payments (6.5.13). TAX = total tax receipts (6.5.1). 6.6 6.6.1 Income Income accounting Total household sector pre-tax income (YJ) (6.6.1) is the sum of income from wages, salaries and self-employment (YE) (6.6.2); current grants to the household sector (YJG) (6.5.12); non-salary income, such as employers’ social contributions (YEC) (6.6.3); and other households’ non-labour income (YDIJ) (6.6.4), such as income from dividends and interest. The macroeconometric model 57 YJt = YEt + YJGt + YECt + YDIJt (6.6.1) Total wages, salaries and self-employed income (YE) is modelled as an identity. The data source for employment is on an LFS rather than a national accounts basis, while YE is a national accounts construct. So a scaling factor is used to reconcile these sources. YEt = 0.0363EARNt . EMPt (6.6.2) where YE = total wages, salaries and self-employed income (6.6.2). EARN = average earnings index (6.3.3). EMP = level of employment in heads (6.3.12). Total employers’ social contributions (YEC) (6.6.3) is proxied by the product of the exogenous rate of employers’ social contributions (REC) and wages, salaries and self-employed income (YE) (6.6.2). YECt = RECt . YEt (6.6.3) Growth in the ratio of households’ non-labour income (YDIJ) to nominal GDP (GDPL) is a function of the nominal interest rate (RS) and a time trend. ∆( ydijt − gdplt ) = − 0.92(( ydijt −1 − gdplt −1 ) + 2.81 ( −5.3) (20.1) RS − 3.34 log1 + t −1 − 0.0072TIMEt −1 ) 400 ( −2.5) ( −7.6) where YDIJ = households’ non-labour income (6.6.4). GDPL = GDP at factor cost in current prices (6.2.4). RS = base rate of interest (6.1.1). TIME = time trend. Adjusted R2: 0.4 Equation standard error: 0.04 LM test for serial correlation: F-stat. = 0.00 [0.96] Normality test: χ2(2) = 0.79 [0.67] Heteroscedasticity: F-stat. = 0.83 [0.58] Sample period: 1988 Q3–1998 Q2 (6.6.4) 58 Economic models at the Bank of England Single-equation dynamic responses: Response of households’ non-labour income to a 1% shock to RHS variables Per cent Quarters ahead Nominal interest rate 1 3.1 4 3.3 8 3.3 Long run (LR) 3.3 50% of LR by 1 quarter 90% of LR by 1 quarter 6.6.2 Real household post-tax income and real labour income Real household post-tax income (RHPI) (6.6.5) is defined as total household sector pre-tax income (YJ) (6.6.1) less tax deductions from household income (TJL) (6.5.2), all deflated by the consumers’ expenditure deflator (PC) (6.4.13). RHPIt = (YJt − TJLt ) PCt (6.6.5) Real post-tax labour income (LY) (6.6.6) is defined as total household sector pre-tax income (YJ) (6.6.1) excluding tax deductions from household income (TJL) (6.5.2) and households’ non-labour income (YDIJ) (6.6.4), all deflated by the consumers’ expenditure deflator (PC) (6.4.13). LYt = (YJt − YDIJt − TJLt ) PCt (6.6.6) The macroeconometric model 59 7 Variables listing Name Description Source(1) Code / Details AVH Average hours worked per person per week / 1,000 ONS YBUS.Q / MGRZ.Q BAL Current account balance (£m current prices) ONS HBOP.Q BALT Nominal goods and services trade balance (£m current prices) ONS BOKI.Q + IKBD.Q BETA 1 – business sector net capital stock depreciation rate BoE BoE construction based on ONS net business sector capital stock and business investment (NPEL.Q) BETANH 1 – whole-economy net capital stock net of housing depreciation rate BoE BoE construction based on ONS net whole-economy capital stock net of housing and non-dwelling investment (NPQT.Q – DFEG.Q) BIPD Balance of interest, dividends and profits (£m current prices) ONS HBOJ.Q BTRF Balance of transfers (£m current prices) ONS IKBP.Q C Consumers’ expenditure (£m 1995 constant prices) ONS ABJR.Q + HAYO.Q CAPU Capacity utilisation BoE Log(YBHH.Q) – 2.7 – 0.7 log(YBUS.Q) – 0.3 log(KNH) – (0.7)(0.004)TIME COMNUS World non-oil commodity prices (index, US$) Datastream ECALLI$ DD Total domestic expenditure (£m 1995 constant market prices) ONS YBIM.Q DI General government debt interest payments (£m current prices) ONS ROXY.Q (1) ONS: Office for National Statistics; BoE: Bank of England; HMCE: HM Customs and Excise Departmental Report, Section 3: Government Policy Changes; DETR: Department of the Environment, Transport and the Regions; IMF: International Monetary Fund; and BIS: Bank for International Settlements. 60 Economic models at the Bank of England Name Description Source Code / Details DPP Domestically consumed output price index ONS/BoE Log(CGCB.Q / YBHH.Q) – 0.2 log(IKBH.Q / IKBK.Q) DUTY Index of duty element of RPI (January 1987 = 100) BoE/ONS Weighted chain-linked average of basket (DOBN.Q + DOBO.Q + DOBH.Q + DOBK.Q + DOCU.Q + DOCV.Q) EARN Average Earnings Index (1995 = 100) ONS LNMQ.Q EDS US dollar-sterling exchange rate (£:US$) ONS AJFA.Q EER Sterling effective exchange rate index (1990 = 100) ONS AJHX.Q EMP Total employment in heads ONS (thousands; including self-employed) MGRZ.Q EMPH Total employment in hours per week ONS (millions) YBUS.Q EQP Equity prices (FTSE All-Share) ONS AJMA.Q EVAT Value-added taxation rate ONS RUDR.Q / (ABJQ.Q + HAYE.Q) FCA Factor cost adjustment (£m 1995 constant prices) ONS ABMI.Q – YBHH.Q FCAL Factor cost adjustment (£m current prices) ONS CMVL.Q FOH Foreign holdings of UK assets (£m current prices) ONS HBQB.Q FVAT Rate of VAT charged on domestic fuel and light HMCE G General government final consumption expenditure (£m 1995 constant prices) ONS NMRY.Q GDP GDP(A) at factor cost (£m 1995 constant prices) ONS YBHH.Q GDPL GDP at factor cost (£m current prices) ONS CGCB.Q The macroeconometric model 61 Name Description Source Code / Details GDPM GDP(A) at market prices (£m 1995 constant prices) ONS ABMI.Q GDPT Trend output BoE 0.063 + 0.7 log(YBTF.Q) + 0.3 log(KNH) + (0.7)(0.004)TIME GHW Gross housing wealth (£m current prices) ONS CGRI.A GL General government final consumption expenditure (£m current prices) ONS NMRP.Q I Fixed investment (£m 1995 constant prices) ONS NPQT.Q + NPJR.Q IBUS Business investment (£m 1995 constant prices) ONS NPEL.Q IG General government investment (£m 1995 constant prices) ONS DLWF.Q IGL General government investment (£m current prices) ONS RNCZ.Q + RNSM.Q IH Private sector dwellings investment (£m 1995 constant prices) ONS DFEA.Q II Change in inventories (£m 1995 constant prices) ONS CAFU.Q INF Four-quarter inflation rate of RPIX ONS Four-quarter percentage growth of CHMK.Q INFE Expectations of annual RPIX inflation BoE 1.1 + 1.2 INF(–1) – 0.6 INF(–2) INOLD Proportion of population over retirement age that is inactive ONS (MGSL.Q – MGRZ.Q – MGSC.Q – YBSN.Q) / (MGSL.Q – YBTF.Q) INWA Proportion of population of working age that is inactive ONS YBSN.Q / YBTF.Q IVAT Rate of VAT charged on insurance HMCE KBUSNH Business non-residential capital stock (£m 1995 constant prices) BoE BETA.KBUSNH(–1) + NPEL.Q KII Stock level (£m 1995 constant prices) ONS ONS starting level + CAFU.Q 62 Economic models at the Bank of England Name Description Source Code / Details KNH Non-residential housing capital stock (£m 1995 constant prices) BoE BETANH.KNH(–1) + (NPQT.Q – DFEA.Q) LY Real post-tax labour income (£m 1995 constant prices) ONS (RPQK.Q – ROYL.Q + ROYT.Q – NRJN.Q + ROYH.Q) / ((ABJQ.Q + HAYE.Q) / (ABJR.Q + HAYO.Q)) M Imports of goods and services (£m 1995 constant prices) ONS IKBL.Q M4 Break-adjusted stock of broad money (£m current prices) BoE Statistical Abstract 1998, Part 2, Table 10, code: VUBR MIPS Mortgage interest payments sub-index of RPI (January 1987 = 1) ONS DOBQ.Q NEA Net external assets (£m current prices) ONS HBQC.Q NFW Net financial wealth (£m current prices) ONS NZEA.Q PA Participation rate of population aged 16 and over ONS (MGRZ.Q + MGSC.Q) / MGSL.Q PC Total final consumers’ expenditure deflator (1995 = 1) ONS (ABJQ.Q + HAYE.Q ) / (ABJR.Q + HAYO.Q) PETSPOT Oil spot prices (average of Brent crude, West Texas, Dubai light; US$) Bloomberg Brent crude: EUCRBRDT Dubai light: PGCRDUBA West Texas: USCRWTIC PG Government expenditure deflator (1995 = 1) ONS NMRP.Q / NMRY.Q PGDP GDP deflator at factor cost (1995 = 1) ONS CGCB.Q / YBHH.Q PHSE UK house prices (1990 = 1, mixed adjusted) DETR PM Import price deflator (1995 = 1) ONS IKBI.Q / IKBL.Q POP Population aged 16 and over ONS MGSL.Q POWA Population of working age (men 16–64 years, women 16–59) ONS YBTF.Q The macroeconometric model 63 Name Description Source Code / Details PSNB Public Sector Net Borrowing (£m current prices) ONS EQLD.Q PTSH Part-time share of employment ONS YCBH.Q / MGRZ.Q PVIC Present value of investment allowances BoE Constructed using approximate allowance schemes for different types of asset weighted by the asset composition of business investment. PX Export price deflator (1995 = 1) ONS IKBH.Q / IKBK.Q RC Effective corporate income taxation rate ONS ACCD.Q / CGCB.Q RCC Real cost of capital ONS/BoE 0.0025(((1 – PVIC) / (1 – (ACCD.Q / CGCB.Q)) (AJLX.Q + (1 – BETA4) 100)) – INFE) RD Deposit rate BoE Σ di .wi i where wi = weights of components in Divisia money and di = rates of return. Monetary and Financial Statistics, Table 7. REC Total effective employers’ social contribution rate ONS ROYK.Q / (ROYJ.Q + ROYH.Q) REM Employers’ effective tax rate ONS 1 + (ROYK.Q / ROYJ.Q) REV Wealth revaluation term Datastream/ ONS 0.12(AJHX.Q(–1) / AJHX.Q) (WEQP /WEQP(–1)) +0.04(AJHX.Q(–1) / AJHX.Q) (US10B.Q(–1) / US10B.Q) +0.01(AJHX.Q(–1) / AJHX.Q) +0.15(AJLX.Q(–1) / AJLX.Q) + 0.64(AJMA.Q / AJMA.Q(–1)) + 0.045 RHPI Real household post-tax income (£m 1995 constant prices) ONS RPQK.Q((ABJR.Q + HAYO.Q) / (ABJQ.Q + HAYE.Q)) RJC Personal sector social contribution rate ONS (RPHU.Q – RVFH.Q) / (ROYJ.Q + ROYH.Q) RJY Effective household income taxation rate ONS RPHS.Q / (ROYJ.Q + ROYH.Q) 64 Economic models at the Bank of England Name Description Source Code / Details RL Redemption yield on long-dated British Government Securities (20 years; per cent per annum) ONS AJLX.Q RLR 10-year index-linked bond spot yield (end quarter) BoE RMI Average rate at which MIRAS is claimed HMCE RMM4 Mortgage interest rate BoE Monetary and Financial Statistics, Table 28.3, code: quarterly average of WBMG RP RPIX inflation adjusted by productivity ONS (CHMK.Q.MGRZ.Q) / YBHH.Q RPCC Council tax and rates sub-index of RPI (January 1987 = 100) ONS DOBR.Q RPI Retail price index (January 1987 = 1) ONS CHAW.Q RPIX RPI excluding mortgage interest payments (January 1987 = 1) ONS CHMK.Q RPIY RPI excluding mortgage interest payments and indirect taxes (January 1987 = 100) ONS CBZW.Q RPXC RPI excluding mortgage interest payments and council taxation (January 1987 = 100) ONS DQAD.Q RRX Real exchange rate, GDP deflator measure Datastream/ ONS (CGCB.Q.AJHX.Q) / (YBHH.Q.WPX) RS London clearing banks’ base rate ONS AMIH.Q RSD Other expenditure taxation rate ONS (NTAB.Q – RUDR.Q) / (ABJQ.Q + HAYE.Q) RSDF Interest rate differential BoE/ONS Log(1 + AMIH.Q / 400) – log(1 + WRS / 400) RTS Effective government subsidy rate ONS AAXW.Q / CGCB.Q RVAT Standard rate of VAT HMCE RXRM Importers’ relative price ONS (IKBI.Q.YBHH.Q) / (IKBL.Q.CGCB.Q) The macroeconometric model 65 Name Description Source Code / Details RXRX Exporters’ real exchange rate Datastream/ ONS (IKBH.Q.AJHX.Q) / (IKBK.Q.WPX) SBEU Subsidies from the European Union ONS AAXW.Q – ROXF.Q SPEC Trade specialisation term BoE Hodrick-Prescott filter of X with λ = 10,000 X = (TRAD / WGDP) SUBS Government subsidies on products (£m current prices) ONS AAXW.Q TAX Total tax receipts (including private pension contributions) (£m current prices) ONS RPHR.Q + ACCD.Q + RPHU.Q – RVFH.Q + CMVL.Q TCC Other current taxes paid by households (£m current prices) ONS RPHT.Q TE Total taxes on production and imports (£m current prices) ONS NTAB.Q TIME Time trend BoE 1963 Q1 = 1 TJL Tax deductions from household income (£m current prices) ONS RPHU.Q – RVFH.Q + RPHR.Q TRAD World trade (1996 = 100) ONS/IMF Average of world import volumes. Weighted by countries’ shares in total UK exports of goods and services in 1996. TSD Other expenditure taxation ONS NTAB.Q – RUDR.Q TVAT Value-added taxation receipts ONS RUDR.Q TXEU Taxes to the European Union ONS FHLE.Q + QYZO.Q + QYZM.Q + CIOG.Q TYC Corporate income taxation receipts (£m current prices) ONS ACCD.Q TYJ Household income tax payments (£m current prices) ONS RPHS.Q UKA UK holdings of foreign assets (£m current prices) ONS HBQA.Q ULC Nominal unit labour cost ONS (LNMQ.Q(1 + (ROYK.Q / ROYJ.Q))MGRZ.Q) / YBHH.Q 66 Economic models at the Bank of England Name Description Source Code / Details UN LFS/ILO unemployment level ONS MGSC.Q UR LFS/ILO unemployment rate ONS MGSC.Q / MGSF.Q USER Real user cost of housing BoE Based on average post-tax mortgage rate (AJNL.Q) USRL US long bond rates BoE Monetary and Financial Statistics, Table 28.2, code: quarterly average of YD10US WCC Weight of council tax and rates in RPI per 1,000 ONS CZXF.A WDUT Weight of duty element in RPI BoE WEL Total household sector wealth (£m current prices) BoE NZEA.Q + GHW WEQP World equity prices (S&P global equity price index) Datastream WIWRLDL(PI) WGDP World GDP (1996 = 100) Datastream Average world GDP weighted by countries’ shares in total UK exports of goods and services in 1996. WMIP Weight of mortgage interest payments in RPI per 1,000 ONS CZXE.A WPX World export prices (1995 = 100) Datastream G7 (excluding UK) weighted average of exports of goods and services deflators; effective exchange rate weights applied. WRPY Weight of RPIY in RPI / 1,000 ONS/BoE 1,000 – sum of weights of VAT, excise duties, local taxation, insurance tax, mortgage interest payments. WRS World nominal interest rate BoE/BIS G7 (excluding UK) weighted average of three-month interbank interest rates; effective exchange rate weights applied. di wi rp i i where wi = weight of good i in RPI basket (parts per 1,000), di = duty on good i and rpi = retail price of good i. ∑ The macroeconometric model 67 Name Description Source Code / Details X Exports of goods and services (£m 1995 constant prices) ONS IKBK.Q YDIJ Households’ non-labour income (£m current prices) ONS ROYL.Q – ROYT.Q + NRJN.Q – ROYH.Q YE Total wages, salaries and self-employment income (£m current prices) ONS ROYJ.Q + ROYH.Q YEC Total employers’ social contributions (£m current prices) ONS ROYK.Q YJ Total household sector pre-tax income (including benefits) (£m current prices) ONS ROYJ.Q + ROYK.Q + RPHL.Q – RPIA.Q + RPHM.Q – RPIB.Q + RPQJ.Q + ROYL.Q – ROYT.Q + NRJN.Q YJC Net social contributions from household sector (£m current prices) ONS RPHU.Q – RVFH.Q YJG Current grants to the household sector (£m current prices) ONS RPHL.Q – RPIA.Q + RPHM.Q – RPIB.Q + RPQJ.Q ZPROXY Measure of structural effects of labour market developments BoE Hodrick-Prescott filter of X with λ = 10,000 X = log[(LNMQ.Q(1 + (ROYK.Q / ROJY.Q)). 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