Equating of psychometric scales and tests is frequently required and conducted in educational, behavioral, and clinical research. Construct comparability or equivalence between measuring instruments is a necessary condition for making decisions about linking and equating resulting scores. This article is concerned with a widely applicable method…

A correlation structure modeling method for comparison of mediated effects is outlined. The procedure permits point and interval estimation of differences in mediator effects, and is useful with models postulating 1 or more predictor, intervening, or response variables that may also be latent constructs. The approach allows scale-free evaluation…

Growth curve analysis is applied to modeling test performance changes demonstrated by older adults following cognitive training or based on repeatedly presented fluid intelligence measures. Findings using data from a study by P. Bates and others (1986) provide evidence of plasticity in the fluid intelligence of older adults. (SLD)

A general structural modeling approach to correlates and predictors of change in multiwave design is discussed. It allows estimation of theoretically and empirically relevant interrelationship indexes between growth and decline in longitudinally assessed psychological constructs and additional variables. Data from a study of aged adults illustrate…

Studied modeling individual latent growth curves of older adults on measures of fluid intelligence by fitting second-order polynomial curves reflecting initial test performance improvement followed by relative stability/drop to the recorded scores of each of 248 subjects. Results suggest substantial plasticity in fluid intelligence of older…

The ability of 248 older adults to improve their performance on fluid intelligence tests, with or without tutor-guided instruction in cognitive skills, was studied using multidimensional longitudinal structural equation models. Results suggest considerable plasticity in adult intellectual function and the capacity to improve performance. (SLD)