A Method for Estimating Treatment Effects When Individuals are Growing

Abstract

In an earlier paper (Bryk & Weisberg, 1976) , we introduced the value-added analysis. This approach built on the notion that many educational programs are dynamic interventions in natural growth processes. In particular, by modeling the natural growth process, we developed an analytic model and estimation procedure for assessing program impact on these growth processes. The present article extends the theory and applications of value-added analysis in several important directions. We present here for practitioners and researchers a coherent overview of the method that emphasizes intuitive rationale and simple data analysis procedures.