Students' ignorance of civics is often viewed with alarm, as in interpretations of the 1998 National Assessment of Educational Progress (NAEP); yet adults' incomplete knowledge of government is considered by many to be reasonable and acceptable. We show that aggregate distributions of political knowledge are actually quite similar for students and adults. However, the types of questions differ greatly: Where adults are typically asked about contemporary politics, students are asked about political institutions. We also show that the construction of NAEP does not permit comparative identification of knowledge levels across sub-topics. Moreover, we note that levels of performance are determined only after the results of the test are known, making it difficult to evaluate the success of civic education. We conclude that understanding student knowledge levels--and thus evaluating civic education--requires careful scrutiny of the content and construction of the NAEP test, and perhaps requires changes that more readily permit comparison of students' performance against pre-established criteria; across topics, states, or time; or between today's students and various generations of adults. (Contains 4 tables, 1 figure and 20 notes.)