Benefits of participating in contingent valuation mail surveys and their effects on respondent behavior: a panel analysis

We investigated the “fringe benefits” of participating in contingent-valuation mail surveys and their effects on respondents' answers. A two-wave panel survey evaluating Japan's anti-global warming policies was conducted. One sample was randomly assigned to either of two survey treatment groups with different survey loads. Factor analyses of answers distinguished the survey fringe benefit factor from the environmental concern factor. The correlation between the two factors was smaller for the heavy load group than for the light load group. Estimations of structural equation models showed that survey participation became higher when the survey fringe benefit factor scored higher. This tendency was found regardless of the survey load level. Structural equation models did not confirm a positive correlation between the survey fringe benefit factor and the consistency of WTP answers across survey waves. However, a logistic regression of the answers from the heavy-load group revealed a positive correlation between the consistency of WTP answers and the level of “perception of the survey as a good cause,” which was highly correlated to the fringe benefit factor in the previous factor analyses. This positive relationship was not detected for the light-load group.