This study investigated the score exchangeability of concept maps with problem-solving essays. Of interest was whether sixth-grade students' concept maps predicted their scores on essay responses that used concept map content. Concept maps were hypothesized to be alternatives to performance assessments for content-area domain knowledge in science. Both special (n = 16) and general (n = 16) education students participated in a science unit that covered three ecosystem cycles: (a) the water cycle, (b) the nitrogen cycle, and (c) the carbon dioxide-oxygen cycle. Assessment tasks required students to draw three concept maps and respond to two essay questions. Results showed that concept maps and essay tasks lacked consistent exchangeability. Findings indicated low predictive validity between map scores and essay scores and, thus, maps should not be considered alternative content-area domain assessments. (Contains 2 tables and 4 figures.)