EXTERNAL TRADE UNIT VALUE INDICES, SLOVENIA
METHODOLOGICAL EXPLANATIONS
PURPOSE OF THE STATISTICAL SURVEY
LEGAL BASIS FOR THE SURVEY
OBSERVATION UNITS
COVERAGE
SOURCES AND METHODS OF DATA COLLECTION
DEFINITIONS
EXPLANATIONS
PUBLISHING
REVISION OF THE DATA
OTHER METHODOLOGICAL MATERIALS
PREPARED BY
LAST UPDATED
PURPOSE OF THE STATISTICAL SURVEY
External trade unit value indices are used for measuring the dynamics of export and import
prices and as deflators for the estimation of real trends in exports/imports of goods.
LEGAL BASIS FOR THE SURVEY
There is no legal basis for this survey. The survey is based on partnership. External trade
unit value indices are calculated for national purposes within the external trade statistics in
most of the world countries. In the Annual Programme of Statistical Surveys the survey is
shown within the task 'Export and import external trade unit value indices ZT-IPVIU/ČL'.
OBSERVATION UNITS
The observation unit in external trade statistics is export or import shipment of goods (trade
transaction) which is included in statistical coverage according to methodological
recommendations.
COVERAGE
The calculation of external trade unit value indices includes all data covered by external trade
statistics, except exports and imports of goods classified into section 9 of the Standard
International Trade Classification (Commodities and transactions n.e.c.) and exports and
imports of goods for which in Slovenia the so-called passive data protection is applied. From
the covered current and base period exports and imports of goods for which in the base year
the variability of unit values, measured with the coefficient of variation, exceeded the
predefined limit, is also excluded.
Classifications used in the presentation of external trade unit value indices:
 Standard International Trade Classification (SITC) of the United Nations;
 Classification by Broad Economic Categories (BEC) of the United Nations;

Standard Classification of Activities (SKD 2008). SKD 2008
(http://www.stat.si/dokument/1209/skd.pdf) is the national version of European
statistical classification of economic activities NACE. Rev. 2
(http://ec.europa.eu/eurostat/documents/3859598/5902521/KS-RA-07-015EN.PDF/dd5443f5-b886-40e4-920d-9df03590ff91?version=1.0), which includes the
entire activities of the European classification and at same time adds some national
subclasses.
Codes listed in the classifications are interoperable with eight digit code of the Combined
Nomenclature.
SOURCES AND METHODS OF DATA COLLECTION
Until Slovenia’s accession to the EU the only source of data for external trade unit value
index calculation was data from customs declarations. Since Slovenia’s accession to the EU
the data sources are two different systems: Intrastat or statistics relating to the trading of
goods between EU Member States (data collected on statistical forms) and Extrastat or
statistics relating to the trading of goods with non-member countries (data from customs
declarations).
Data in Extrastat are acquired from the administrative data source (i.e. customs
declarations); data are reported monthly to the Statistical Office of the Republic of Slovenia
(SURS) by Financial Administration of the Republic of Slovenia (FURS) on electronic media.
Data in Intrastat are acquired directly from business entities on statistical questionnaires.
Data can be reported electronically (using the system for electronic data interchange or via a
web form) or on paper forms. The required information is usually retrieved from the business
entity’s accounting records, i.e. from the data available on the issued or received invoices
and from the data available on transport documentation, which accompany each export and
import shipment of goods.
For external trade unit value index calculation only data on the statistical value of exported
and imported goods in EUR, data on net mass, data on quantity in supplementary unit and
some other data necessary for the calculation at the most disaggregated level of the
Combined Nomenclature are used.
DEFINITIONS
The unit value is the average value (not the price of a determined product) per kilogram (or
quantity in supplementary unit) of all products classified under the same eight-digit code of
the Combined Nomenclature. The selection of appropriate quantity (net mass in kilograms or
quantity in supplementary unit) used in the calculation of the unit value of the individual
product depends on both coefficients of variation (the coefficient of variation for the unit value
calculated using data on kilograms and the coefficient of variation for the unit value
calculated using data on quantity in supplementary unit) for this product in the base year. In
cases when not only one product but more products of different kinds or different quality are
classified under the same eight-digit code of the Combined Nomenclature, the relative
change of the unit value can reflect the change of the price as well as the change of
composition or quality of goods. Nevertheless, the aggregated external trade unit value
indices, calculated for larger groups of goods, are appropriate for monitoring price
developments in external trade and as deflators.
The observation period is the calendar quarter. External trade unit value indices for
individual quarters and individual flows of goods (export or import) are shown as:
 the index of the observed quarter of the current year compared to the same quarter of
the previous year;
 the index of the observed quarter of the current year compared to the average of the
previous year;
 the cumulative index of all observed quarters of the current year compared to the
same cumulative period of the previous year.
In calculating external trade unit value indices statistical value of goods in EUR is taken into
account. The statistical value of goods is the value of goods on the Slovenian border
(insurance and freight costs are added to or subtracted from the transaction value depending
on delivery terms).
EXPLANATIONS
The method used for unit value index calculation is one of the established methods of
calculating price indices and is used in external trade statistics in line with the
recommendations of the United Nations Statistical Office. External trade unit value indices
are calculated as chain indices by the Laspeyres (IL), Paasche (IP) and Fisher (IF)
formulas. They are published as the Fisher indices.
The formulas for calculation:
∑
∑
∑
∑
√
P1 - unit value at the eight-digit commodity level of the Combined Nomenclature in the current
year
P0 - unit value at the eight-digit commodity level of the Combined Nomenclature in the base
year
V1 – statistical value in EUR at the eight-digit commodity level of the Combined Nomenclature
in the current year
V0 – statistical value in EUR at the eight-digit commodity level of the Combined Nomenclature
in the base year
In the procedure of the external trade unit value indices calculation various methods for data
quality control and improvement of the results are used. Eliminated from calculation are
those individual items from customs declarations (Extrastat) and statistical forms (Intrastat) of
the current and base year:
 in which the data on quantity or statistical value are missing;
 whose value per kilogram (or quantity in supplementary unit) exceeds the interval
“value of the first/third quartile for the unit value at the level of the eight-digit code of
the Combined Nomenclature in which the commodity from the individual item is
classified -/+ 2 * interquartile range”; the lower and upper limits of interval for
individual eight-digit code of the Combined Nomenclature are calculated from
exports/imports data under this code for the entire base year.
The calculation also excludes all goods classified into the same eight-digit code of the
Combined Nomenclature for which the calculated unit value index at the most disaggregated
level of the Combined Nomenclature is above the upper limit or below the lower limit (the
limits within which the indices are believed to be still acceptable are set on the basis of
experience and agree with international practice).
PUBLISHING
Release dates for external trade unit value indices depend on release dates of detailed
data on Slovenia’s trade in goods with foreign countries. The external trade unit value indices
are normaly published 75 days after the observation period.
Quarterly:
 First Release. External trade
 SI-STAT data portal
Annually:
 Slovenia in Figures
 Statistical Yearbook of the Republic of Slovenia1
 SI-STAT data portal
The results of this survey are published as indices based on absolute and seasonally
unadjusted external trade statistical data. Detailed data on external trade unit value indices
are presented in tables on the SI-STAT data portal; data are shown for each quarter
separately for each flow of goods (exports or imports). Indices are shown at the section and
division level of the Standard International Trade Classification (SITC), at the section and
division level of the Standard Classification of Activities (NACE) and according to the
Classification by Broad Economic Categories (BEC). Detailed data on external trade unit
value indices are available for Slovenia’s total trade, for Slovenia's trade with euro area and
for Slovenia's trade with non-euro area.
1
Until reference year 2012.
REVISION OF THE DATA
Data on external trade unit value indices for individual observed quarters of the current year
are provisional when published for the first time, since they are calculated from provisional
external trade data for the current year.
Final data on external trade unit value indices for the fourth quarter of the previous year (they
include data on annual external trade unit value indices for the previous year) are generally
published not later than on 15 July of the current year. With the publication of final data for
the fourth quarter of the previous year, on the SI-STAT data portal the data on external trade
unit value indices for the first three quarters of that year are revised.
After publishing final data, data on external trade unit value indices can exceptionally be
revised, especially due to unforeseen changes in Intrastat and Extrastat methodology or due
to major changes in data that occur due to mandatory reconciliation of asymmetries in
external trade data required by the European Commission or due to later discovery of other
major data discrepancies (inconsistencies).
Methodological explanations about data revision at SURS are published on the website
http://www.stat.si/dokument/5299/RevisionOfStatisticalDataMEgeneral.pdf.
OTHER METHODOLOGICAL MATERIALS
/
PREPARED BY:
Simon Perše, Jana Živec
LAST UPDATED:
22.1.2015