This tutorial addresses possible sources of confusion in interpreting trait scores from the bifactor model. The bifactor model may be used when subscores are desired, either for formative feedback on an achievement test or for theoretically different constructs on a psychological test. The bifactor model is often chosen because it requires fewer…

Variation in test performance among examinees from different regions or national jurisdictions is often partially attributed to differences in the degree of content correspondence between local school or training program curricula, and the test of interest. This posited relationship between test-curriculum correspondence, or "alignment,"…