202
F R E D E R I C K E T A L .
point estimates for the discount rate ranging from 5 to 14%, and Gourinchas and
Parker (2001) report point estimates of 4.0 to 4.5%. Field studies of this type have
the advantage of not assuming isolation, because integrated decision making is
built into the model. Yet such estimates often depend heavily on the myriad as-
sumptions included in the structural model.
34
Recently, Warner and Pleeter (2001) analyzed decisions made by U.S. military
servicemen. As part of military downsizing, over 60,000 military employees were
given the choice between a onetime, lump-sum payment and an annuity payment.
The sizes of the payments depended on the employee’s current salary and number
of years of service—for example, an “E-5” with 9 years of service could choose
between $22,283 now versus $3,714 every year for 18 years. In general, the pres-
ent value of the annuity payment equaled the lump-sum payment for a discount
rate of 17.5%. Although the interest rate was only 7% at the time of these decisions,
more than half of all military officers and more than 90% of enlisted personnel
chose the lump-sum payment.
35
This study is particularly compelling in terms of
credibility of reward delivery, magnitude of stakes, and number of subjects.
36
The benefit of field studies, as compared with experimental studies, is their high
ecological
validity. There is no concern about whether estimated discount rates
would apply to real behavior because they are estimated from such behavior. Yet field
studies are subject to additional confounds due to the complexity of real-world deci-
sions and the inability to control for some important factors. For example, the high
discount rates implied by the widespread use of inefficient electrical appliances
might not result from the discounting of future cost savings per se, but from other
considerations, including: a lack of information among consumers about the cost
savings of the more efficient appliances; a disbelief among consumers that the cost
savings will be as great as promised; a lack of expertise in translating available infor-
mation into economically efficient decisions; or hidden costs of the more efficient
appliances, such as reduced convenience or reliability, or, in the case of lightbulbs,
because the more efficient bulbs generate less aesthetically pleasing light spectra.
37
EXPERIMENTAL STUDIES
Given the difficulties of interpreting field data, the most common methodology
for eliciting discount rates is to solicit “paper and pencil” responses to the prospect
of real and hypothetical rewards and penalties. Four experimental procedures are
commonly used: choice tasks, matching tasks, pricing tasks, and ratings tasks.
34
These macroeconomics studies are not included in the tables and figures, which focus primarily
on individual-level choice data.
35
It should be noted, however, that the guaranteed payments in the annuity program were not in-
dexed for inflation, which averaged 4.2% during the 4 years preceding this choice.
36
Warner and Pleeter (2001) noted that if everyone had chosen the annuity payment, the present
value of all payments would have been $4.2 billion. Given the choices, however, the present value of
the government payout was just $2.5 billion. Thus offering the lump-sum alternative saved the federal
government $1.7 billion.
37
For a criticism of the hidden-costs explanation, however, see Koomey and Sanstad (1994) and
Howarth and Sanstad (1995).
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