General normal ogive and logistic multiple-group models for paired comparisons data are described. In these models, scale value and discriminal dispersion parameters are allowed to vary across stimuli and respondent populations. Model fitting and hypothesis testing are illustrated using health care coverage data from two age groups. (SLD)

An approximate statistical test is derived for the hypothesis that the intraclass reliability coefficients associated with two measurement procedures are equal. Control of Type 1 error is investigated by comparing empirical sampling distributions of the test statistic with its derived theoretical distribution. A numerical illustration is…

Research on the direct-product model is extended by deriving hierarchically nested models for explicitly testing the patterns of method and trait factors and through formal tests developed for the pattern of communalities. These procedures are illustrated, and use of the MUTMUM computer program is discussed. (SLD)

A multidimensionality-based differential item functioning (DIF) analysis paradigm is presented that unifies substantive and statistical DIF analysis approaches by linking both to a theoretically sound and mathematically rigorous multidimensional DIF conceptualization. This approach results in the potential for DIF analysis more closely integrated…

Analysis of hypothetical data with dependent responses demonstrates how information loss caused by the overt response scale has an unknown influence on effect sizes in moderated regression analysis. The number of scale steps measuring the dependent variable results in a form of systematic error that alters interaction effect sizes. (SLD)

Textbook calculations of statistical power or sample size follow from formulas that assume that the variables under consideration are measured without error. However, in the real world of behavioral research, errors of measurement cannot be neglected. The determination of sample size is discussed, and an example illustrates blocking strategy.…