Work on item response theory was extended to two areas not extensively researched previously, including models for: (1) test items that require more than one ability for a correct response (MIRT); and (2) interaction between modules of instruction that have a hierarchical relationship (HST). In order to develop the MIRT and HST models, the author…

Describes a new approach for analyzing an individual's responses made at multiple times. Proposes that three sources of variance determine a person's current standing on a variable: trait (term does not change), state (term changes), and error (random term). Shows how structural equation modeling can be used and presents an extended example. (RJM)