This manual is a technical resource for helping drug treatment program directors decide whether to do a follow-up of a client population and, if so, how to do one. Each chapter was written by a particular set of authors. However, the points contained in the chapters had to receive the general agreement of a committee whose membership included…

This manual is intended to improve both the design of longitudinal studies and analysis of the resulting data. Issues related to educational and developmental research have been emphasized in these eight chapters. Topics of particular interest to longitudinal researchers include stochastic models of developmental change, mathematical…