1 Social experiments are programs conducted as field research projects meant to test one or more hypotheses. Although they often provide services, the services are secondary in importance to the data sought by the investigators. Outcome and impact evaluations using robust quantitative measures are generally appropriate to this type of project. Demonstration projects are not justified primarily by their research value, as are social experiments. Demonstration projects are more commonly treated as prototype programs, and process evaluation is usually conducted to determine how well the program can be implemented.
Developmental programs are usually smaller scale trials to test an innovative idea.
The evaluator often wants to know if the idea can work in practice, and under what circumstances. Process evaluation is often most important in this setting as well. New programs are settings in which new services are being offered in addition to other existing services. In this setting, the new program may not have been fully thought out at the onset and unforeseen factors may influence its implementation. The evaluator often has little control over the program design or comes to the project too late to design an adequate study.