DELPHI SURVEY ON THE ECONOMIC APPRAISAL OF INVESTMENT PROJECTS IN AN
INTERGENERATIONAL CONTEXT (2nd Round)
In this survey you are able to see the results of the first round. Questions 1 to 8 are given alongside the frequency of distribution (in
percentage points with the modal value in bold) of the scores given by the entire panel of experts, with your own score marked with
an X. In question 9 we give the means and standard deviations. On the right you are asked to answer the question again, irrespective
of whether you decide to reconsider (modify) it or not. We would remind you that the scale is from -2 (total disagreement) and 2 (total
agreement), with 0 indicating a neutral position (check the corresponding box).
RESULTS 1st ROUND (%)
-2
1. Cost-Benefit Analysis is the appropiate method to use for the 8,3
economic appraisal of public investment projects, including those with
intergenerational impact.
2. The social discount rate should be reconsidered in
1,8
intergenerational settings with time horizons of several centuries,
because the standard discount rate is only appropriate in the case of
projects with time horizons of a few decades.
3. A lower social discount rate should be used in intergenerational 3,7
contexts, in order to assign more weight to benefits and costs that arise
in the long and very long term (sustainability).
4. The only valid discount rate in intergenerational contexts would be 0 36,7
%.
5. The value of the social discount rate should be linked to the time 5,8
horizon of the project (a “Weitzman” or “Green book” scheme, or
similar).
6. The value of the social discount rate should be linked to the 14
characteristics and type of the natural resource that experiences
the impact.
7. In time horizons of centuries, it is better to use a time
8,4
variable discount factor (such as hyperbolic
discounting) rather than a constant factor
( exponential )
8. One option to bear in mind is the simultaneous use of different 8,9
discount rates for tangible and intangible effects in the same CBA.
REPONSES 2nd ROUND
-1
0
1
2
-2
16,5
10,1
28,4
36,7
2,7
9,1
30
56,4
3,7
15
31,8
45,8
17,4
9,2
15,6
21,1
7,7
9,6
43,3
33,7
21
18
27
20
6,3
12,6
33,7
38,9
15,8
23,8
29,7
21,8
9. If you agree that the time horizon for the project is a variable that that should be considered
when selecting the intergenerational discount rate (that is, if you gave a rating of 0, +1 or +2
in question 5), please indicate the rates you consider reasonable in projects with different
time horizons (score or interval):
10. 1
Time horizon
0 -30
10. 2
Time horizon
31 a 75
10. 3
Time horizon
76 a 125
10. 4
Time horizon
126- 200
10. 5
Time horizon
201-300
10. 6
Time horizon
Over 300
Filling with a cross the appropriate:
I do not read additional information package
I do read the additional information package
Other:
THANK YOU VERY MUCH FOR YOUR TIME
ADDITIONAL COMMENTS:
Mean
Standard
deviation
3,72 %
2,94 %
2,13 %
1,79 %
1,28%
1,07%
1,28
1,13
1,30
1,18
1,37
1,24
-1
0
Your first
response
1
2ªRound
response
2
DK/N
A
DK/NA