The effective use of contextual analysis - the study of the role of group context on actions and attitudes of individuals - often involves overcoming a number of issues such as group boundaries, the mobility of individuals within a group, overlapping groups, missing individual data and the choice of statistical models. This straightforward volume offers researchers a guide for selecting the best model to use, and discusses such topics as contextual analysis with absolute effects, with relative effects and the choice between regression coefficients as fixed parameters or as random variables.