This study evaluated the impact of unequal reliability on test equating methods in the nonequivalent groups with anchor test (NEAT) design. Classical true score-based models were compared in terms of their assumptions about how reliability impacts test scores. These models were related to treatment of population ability differences by different…

Using several data sets, the relative performance of the beta binomial model and two more general strong true score models in estimating several indices of classification consistency is examined. It appears that the beta binomial model can provide inadequate fits to raw score distributions compared to more general models. (TJH)

Two methods of 'equating' tests using item response theory (IRT) are compared, one using true scores, the other using the estimated distribution of observed scores. On the data studied, they yield almost indistinguishable results. This is a reassuring result for users of IRT equating methods. (Author)

Five-hundred dichotomously scored response patterns were generated with sequentially independent (SI) items and 500 with dependent (SD) items for each of thirty-six combinations of sampling parameters (i.e., three test lengths, three sample sizes, and four item difficulty distributions). KR-20, KR-21, and Split-Half (S-H) reliabilities were…

The problem of the comparability of change scores is investigated. Change quotients and residual change scores are evaluated as alternative approaches and methods for estimating the true change and true score residual, the reliability of change scores and residuals, and procedures for constructing confidence intervals for residuals are explored.…