ABSTRACT
Repeated measurements are used quite often in research studies to examine temporal change processes in individuals or groups. One reason for their popularity in the social and behavioral disciplines is that repeated measurements allow researchers to investigate individual (intraindividual) development across time as well as between-individual (interindividual) differences and similarities in change patterns. For example, educational researchers may be interested in examining patterns of growth in ability exhibited by a group of subjects in longitudinally administered measures following some treatment program and relating them to various characteristics of students and environments they live in. The researchers may also be interested in comparing the rates of change in these variables across several student populations, or in studying the correlates and predictors of growth in ability over time in an effort to determine which students exhibited the fastest improvement in ability. Alternatively, developmental scientists may be interested in studying cognitive functioning decline in later life, comparing its pattern across gender, socio-economic, or education related subpopulations of elderly, as well as finding out the antecedents, correlates, and predictors of this decline.
