Public Opinion Quarterly Advance Access published online on September 21, 2007
Public Opinion Quarterly, doi:10.1093/poq/nfm032
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An Experiment on the Measurement of Political Knowledge in Surveys
Address correspondence to Patrick Sturgis; e-mail: p.sturgis{at}surrey.ac.uk.
In a series of articles, Mondak and colleagues argue that the conventional way of measuring political knowledge in surveys is flawed. Personality related "propensity to guess" underestimates the level of political knowledge in the population and distorts estimates of between group differences, when a DK alternative is offered. This has led Mondak to recommend the use of closed-ended items on which DKs are not explicitly offered, following best practice in the field of educational testing. In this article, we present the results of an experimental study which calls into question the wisdom of this approach. Our results show little evidence of partial knowledge concealed within DK responses; when people who initially select a DK alternative are subsequently asked to provide a "best guess," they fare statistically no better than chance. We conclude that opinion researchers should be cautious about adopting Mondak's recommendations for the design of political knowledge items in surveys.
Received for publication February 22, 2005. Revision received October 19, 2006. Accepted for publication October 25, 2006.
PATRICK STURGIS AND NICK ALLUM are with the Department of Sociology, University of Surrey, Guildford, Surrey, UK. PATTEN SMITH is with Ipsos-MORI, 77-81 Borough Road, London, SE1 1FY, UK. This research was funded under a joint grant from the University of Surrey University Research Support Fund and BMRB International Limited. We extend our gratitude to the editor of this journal and five anonymous reviewers, whose comments substantially improved earlier drafts of this manuscript.