An experiment on the measurement of political knowledge in surveys

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.