While many analysts use PK scales to make claims about what people know and why it matters, others use subjective interviewer assessments. The ANES is a common source of these assessments. The ANES asks its interviewers to offer “a five-level summary evaluation of each respondent’s level of information level.” Interviewers rate each respondent as “very high,” “high,” “average,” “fairly low,” or “very low.” Data from these assessments appear in widely cited academic articles on political ignorance. In one such article, Bartels (1996: 203) argues that this variable’s use is preferable to PK scales. He claims that interviewer assessments are . . . no less (and sometimes more) strongly related than factual information scales are to relevant criterion values such as political interest, education, registration, and turnout (Zaller 1985: 4). Given the added difficulty of making comparisons from one election year to another using scales based on rather different sets of available information items of variable quality, the simpler interviewer ratings seem preferable for my purposes here. . . . Other scholars have augmented the case for using interviewer assessments in attempts to understand the relationship between knowledge and other factors. As Claassen and Highton (2006: 415) write: . . . To measure political information, we rely on NES interviewer ratings of respondents’ levels of political information. This indicator has two primary virtues. First, it is present in each of the surveys we analyze providing a consistent measure across survey years. Second, it has proven to be a valid measure. Bartels used it to provide important insights into public opinion toward … information effects in presidential voting (Bartels, 1996). Given our focus on changing information effects over time, we share the view that because of the “added difficulty of making comparisons from one election year to another using scales based on rather different sets of available information items of variable quality, the simpler interviewer ratings seem preferable.” . . . In a footnote (2006: 415n), they continue the argument: . . . For the purposes of this paper, we also prefer the interviewer rating to measures of policy specific information. . . .