The dynamic factor model proposed by P. C. Molenaar (1985) is exhibited, and a dynamic nonstationary factor model (DNFM) is constructed with latent factor series that have time-varying mean functions. The use of a DNFM is illustrated using data from a television viewing habits study. (SLD)

Asymptotic distributions of H. Brogden's and F. Lord's modified sample biserial correlation coefficients (SBCCs) are derived. Asymptotic variances of these estimators are evaluated for bivariate normal populations and compared to the maximum likelihood estimator's asymptotic variance. These estimators are less variable than ordinary SBCCs when the…

The reliability of residual scores created in the analysis of covariance in pretest-posttest designs, adjusted for a singe covariate, is compared with that of simple difference scores as relevant parameters vary. Little gain in reliability is created by analysis of covariance, which also suffers from reliability problems. (SLD)

A general structural equation model for measuring residualized true change and studying patterns of true growth or decline is described. This approach allows consistent and efficient estimation of the degree of interrelationship between residualized change in a repeatedly assessed psychological construct and other variables. (SLD)

This report describes new statistical procedures for item response analysis using estimation of item response curves used in mental testing with ability parameters treated as a random sample. Modern computer technology and the EM algorithm make this solution possible. The research focused on the theoretical formulation and solution of maximum…

A test theory using only ordinal assumptions is presented, based on the idea that the test items are a sample from a universe of items. The sum across items of the ordinal relations for a pair of persons on the universe items is analogous to a true score. (SLD)

In this paper, algorithms are described for obtaining the maximum likelihood estimates of the parameters in log-linear models. Modified versions of the iterative proportional fitting and Newton-Raphson algorithms are described that work on the minimal sufficient statistics rather than on the usual counts in the full contingency table. This is…

Formulas are provided for estimating the reliability of a linear composite of non-equivalent subtests given the reliabilities of component subtests. The reliability of the composite is compared to that of its components. An empirical example uses data from 170 children aged 4 through 8 years performing 34 Piagetian tasks. (SLD)

A detailed investigation of the statistical procedure of W. Stout (the computer program DIMTEST) for testing the hypothesis that an essentially unidimensional latent trait model fits observed binary response data from a psychological test is presented. One finding is that DIMTEST may fail to perform as desired in the presence of guessing when…

The statistical power of analysis of covariance (ANCOVA) and its advantages over simple analysis of variance are examined in some experimental situations, and an algorithm is proposed for its proper application. In nonrandomized experiments, an ANCOVA is generally not a good approach. (SLD)

A method for analyzing test-item responses is proposed to examine differential item functioning (DIF) in multiple-choice items within the latent class framework. Different models for detection of DIF are formulated, defining the subgroup as a latent variable. An efficient estimation method is described and illustrated. (SLD)