The success of standards-based education systems depends on two elements: strong standards, and assessments that measure what the standards expect. States that have or adopt test-based accountability programs claim that their tests are aligned to their standards. But there had been, up to this point, no independent methodology for checking alignment. This paper describes and illustrates such a methodology and reports results on a sample of state tests. In general, individual test items are reasonably well matched to the standards they are meant to assess. But the collection of items in a test tend to measure only a few of the less challenging standards and objectives. As a result, few state tests can be said to be well-aligned assessments of challenging standards.