Coherence is the core principle underlying standards-based educational reforms. Assessments aligned with content standards are designed to guide instruction and raise achievement. The authors investigate the coherence of standards-based reform's key instruments using the Surveys of Enacted Curriculum. Analyzing 138 standards-assessment pairs spread across grades and the three No Child Left Behind tested subjects, the authors find that roughly half of standards content is tested on the corresponding test and roughly half of test content corresponds to the standards. A moderate proportion of test content is at the wrong level of cognitive demand as compared to the corresponding standards, and vice versa. Between 17% and 27% of content on a typical test covers topics not mentioned in the corresponding standards. Policy and research implications are discussed. (Contains 5 tables and 3 figures.)