Compared four mapping item methods using data from the physical science test of the National Assessment of Educational Progress and studied the opinions of science content area experts about the difficulty of the items through a survey completed by 148 science teachers or scientists. Results of model-based mapping methods were more concordant with…

The unfulfilled promise of criterion-referenced measurement is that it would permit valid inferences about what a student could and could not do. To come closest to achieving all that criterion-referenced testing originally promised, tests of higher item density, with more items per amount of domain, are required. (SLD)