Knowledge Variables in Cross‐National Social Inquiry

Objectives. This article examines the impact of “don't know” responses on cross‐national measures of knowledge regarding science and the environment. Specifically, we explore cross‐national variance in aggregate knowledge levels and the gender gap in knowledge in each of 20 nations to determine whether response‐set effects contribute to observed variance. Methods. Analyses focus on a 12‐item true‐false knowledge battery asked as part of a 1993 International Social Survey Program environmental survey. Whereas most research on knowledge codes incorrect and “don't know” responses identically, we differentiate these response forms and develop procedures to identify and account for systematic differences in the tendency to guess. Results. Substantial cross‐national variance in guessing rates is identified, variance that contributes markedly to variance in observed “knowledge” levels. Also, men are found to guess at higher rates than women, a tendency that exaggerates the magnitude of the observed gender gap in knowledge. Conclusions. Recent research has suggested that “don't know” responses pose threats to the validity of inferences derived from measures of political knowledge in the United States. Our results indicate that a similar risk exists with cross‐national measures of knowledge of science and the environment. It follows that considerable caution must be exercised when comparing data drawn from different nations and cultures.