Public Opinion Quarterly Advance Access originally published online on November 26, 2008
Public Opinion Quarterly 2008 72(5):866-891; doi:10.1093/poq/nfn062
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This article appears in the following Public Opinion Quarterly issue: Special Issue: Web Survey Methods [View the issue table of contents]
Eliciting Subjective Probabilities in Internet Surveys
Individuals’ subjective expectations are important in explaining heterogeneity in individual choices, but their elicitation poses some challenges, in particular when one is interested in the subjective probability distribution of an individual. We have developed an innovative visual representation for Internet surveys that has some advantages over previously used formats. In this paper we present our findings from testing this visual representation in the context of individuals’ Social Security expectations. Respondents are asked to allocate a total of 20 balls across seven bins to express what they believe the chances to be that their future Social Security benefits would fall into any one of those bins. Our data come from the Internet survey of respondents to the Health and Retirement Study, a representative survey of the U.S. population aged 51 and older. To contrast the results from the visual format with a previously used format, we divided the sample into two random groups and administered both, the visual format and the more standard percent chance format. Our findings suggest that the main advantage of the visual format is that it generates usable answers for virtually all respondents in the sample while in the percent chance format a significant fraction (about 20 percent) of responses is lost due to inconsistencies. Across various other dimensions, the visual format performs similarly to the percent chance format, leading us to conclude that the bins-and-balls format is a viable alternative that leads to more complete data.
ADELINE DELAVANDE AND SUSANN ROHWEDDER are with the RAND Corporation, 1776 Main Street, Santa Monica, CA 90407-2138, USA. ADELINE DELAVANDE is also with Universidade Nova de Lisboa, 1099-032 Lisboa, Portugal. This research was supported by a grant from the National Institute on Aging (P01AG008291). Rohwedder is grateful for additional funding from the National Institute on Aging provided under grant R03AG024269. We would like to thank Norbert Schwarz and other participants of the 2007 conference on "Subjective Probabilities and Expectations: Methodological Issues and Empirical Application to Economic Decision-Making" in Jackson, Wyoming for helpful comments on an early draft of this paper. We are also grateful to two anonymous referees and the editor for their constructive advice.