Research on democratic attitudes has recently turned to examine citizens’ views about the performance of specific democratic institutions in their country. Drawing on data from the European Social Survey (ESS6) and the Bright Line Watch Project (BLW) in the United States, this article argues that such evaluative questions carry high levels of cognitive complexity that lead to gender gaps in item response rates. We then show that those gender gaps are present at every level of political knowledge and tend to be wider the less respondents know about the political system. Since women also tend to be more critical of democratic institutions, these results indicate that item non-response biases can make researchers underestimate overall levels of dissatisfaction with democracy, as well as overlook specific groups that may be particularly dissatisfied with the performance of certain parts of the democratic system.