Hypothetical bias: a new meta-analysis

Abstract

Participants in hypothetical surveys or referenda typically express higher values for goods than do participants faced with similar choices in which the stakes involve real money. Previous meta-analyses have confirmed the widespread presence of hypothetical bias in stated preference studies and have identified certain factors associated with higher or lesser degrees of bias. These studies, and indeed the broader stated preference valuation literature, have not offered any definitive insights that can reliably be used to eliminate these biases. The earlier meta-analyses are now dated and were based on a limited number of studies. In this chapter we assess the evidence from the literature up to the present time on hypothetical bias. We include many more papers touching on hypothetical bias than were available to or used by the authors of the prior meta-analyses. We also add two variables (not analyzed in the existing literature) to our meta-analysis: one that is designed to capture whether the good in question is likely to be perceived as familiar or unfamiliar to the study’s survey participants and a second that indicates whether or not the valuation of the good in question is largely or exclusively generated by non-use considerations. In the remainder of this chapter, we first discuss how our meta-data were created. We then identify and briefly discuss some of the issues in survey design that have been hypothesized to contribute to the presence or extent of the hypothetical bias exhibited in various studies. We then present results from a regression analysis of the meta-data, and follow with some concluding remarks.