Longitudinal models of reliability and validity: A latent curve approach

Abstract

The concepts of reliability and validity and their associated coefficients typically have been restricted to a single measurement occasion. This paper describes dynamic generalizations of reliability and validity that will incorporate longitudinal or developmental models, using latent curve analysis. Initially a latent curve model is formulated to depict change. This longitudinal model is then incorporated into the classical definitions of reliability and validity. This approach permits the separation of constancy or change from the indexes of reliability and validity. Statistical estimation and hypothesis testing be achieved using standard structural equations modeling computer programs. These longitudinal models of reliability and validity are demonstrated on sociological psychological data. Index terms: concurrent validity, dynamic models, dynamic true score, latent curve analysis, latent trajectory, predictive validity, reliability, validity.