LONGITUDINAL MODELS OF RELIABILITY AND VALIDITY - A LATENT CURVE APPROACH

The concepts of reliability and validity and their associated coeffici ents typically have been restricted to a single measurement occasion. This paper describes dynamic generalizations of reliability and validi ty that will incorporate longitudinal or developmental models, using l atent curve analysis. Initially a latent curve model is formulated to depict change. This longitudinal model is then incorporated into the c lassical definitions of reliability and validity. This approach permit s the separation of constancy or change from the indexes of reliabilit y and validity. Statistical estimation and hypothesis testing may be a chieved using standard structural equations modeling computer programs . These longitudinal models of reliability and validity are demonstrat ed on sociological and psychological data.