Importance of Appraising Responses of Subgroups in Program Evaluations: The Youth Conservation Corps

A sample of applicants to the 1979 Youth Conservation Corps (YCC) program were surveyed twenty-six months after camp to assess possible long-term perceived benefits to program participants. Successful applicants (enrollees) served as the experimental group, unsuccessful applicants as the control group. Mean score differences on ten scales used for testing showed a consistent pattern of small benefits for the experimental group. When the treatment and control groups were categorized into increasingly definitive subgroups based on socioeconomic and demographic background variables, the magnitude of mean score differences increased greatly for certain subgroups of enrollees. Particular subgroups of enrollees showed sizable benefits not realized by other subgroups, especially when two classifying variables were used to define subgroups.