Attitude strength is an important, but contested, subject in social psychology. Political scientists often rely on measures of attitude strength such as attitude importance, accessibility, or certainty in their work while ignoring the politically meaningful differences across types of strength. This omission is particularly relevant in the discussion of the formation of candidate evaluations. The research reported here indicates that accessibility is not the relevant type of attitude strength when describing how voters use issues in evaluating candidates. Instead, voters' reliance on issues when evaluating candidates depends on the voter's certainty about where the candidates stand. Given the different antecedents of certainty and accessibility, this result suggests that that citizens are able to more carefully process and use information available to them during an election campaign than would be expected by the prevailing theories of attitude formation.