Test-Retest Reliability of Contingent Valuation with Independent Sample Pretest and Posttest Control Groups

Test-retest, the standard method used to investigate reliability of contingent valuation, is limited because when the time period between the two surveys is relatively short the study may exhibit testing recall. Conversely, when the time between the two surveys increases there is an increased chance the true value will change. The test-retest design cannot isolate these effects. Independent pretest and posttest control groups allow testing of reliability even when recall occurs or the true value changes. Using this design, we found ex post estimates of Hicksian surplus are reliable regardless of whether respondents have direct experience with an activity.