This article discusses the use of propensity scoring in experimental program evaluations to estimate impacts for subgroups defined by program features and participants' program experiences. The authors discuss estimation issues and provide specification tests. They also discuss the use of an overlooked data collection design--obtaining predictions…

An experimenting society is one that vigorously tries out proposed solutions to recurrent problems and then tries other alternatives if evaluation shows that previous efforts are ineffective or harmful. Methods that social scientists could use if the experimenting society becomes a reality are explored. (SLD)