and Overview.- The SAT as a Social Indicator: A Pretty Bad Idea.- Discussion 1: The SAT as a Social Indicator: A Pretty Bad Idea.- Self-Selection and Performance-Based Ratings: A Case Study in Program Evaluation.- Discussion 2: Self-Selection and Performance-Based Ratings: A Case Study in Program Evaluation.- Discussion 3: Alternative Methods for Evaluating the Impact of Intervention.- Alternative Methods for Solving the Problem of Selection Bias in Evaluating the Impact of Treatments on Outcomes.- Comments.- Postscript: A Rejoinder to Tukey.- Selection Modeling Versus Mixture Modeling with Nonignorable Nonresponse.- Discussion 4: Mixture Modeling Versus Selection Modeling with Nonignorable Nonresponse.- A Comment on Remarks by Rubin and Hartigan.- Author Index.