A study examined: (1) the feasibility of using concept maps as a measure of content achievement; and (2) whether these measures were sensitive to knowledge learned after reading expository text. Subjects, 131 eighth-grade students, were taught a mapping technique which required them to analyze ideas into propositions and then arrange them into concept maps. Some students were assigned to one of two groups: one group read a content passage; the other read the passage and saw slides. The remaining students were in a control group which received no instruction. All students took a mapping test, a short answer "classroom-type" test, and an attitude questionnaire. Results showed that most students from all ability groups learned to use the mapping technique. Scores from the mapping test were more sensitive to the increases in knowledge gained by reading and seeing the slide presentation than were those from the short-answer test. In addition, the mapping test scores correlated with other indices of schooling progress such as classroom grades and standardized measures of achievement. Although the diagnostic value of the tests seemed to be substantive and could be helpful to teachers and students as they attempt to determine what they do and do not understand, students did not express a positive attitude toward the mapping tests, as indexed by the attitude questionnaire. (Five figures and seven tables of data are included, and 25 references are attached.) (Author/SR)