The existing literature on STW contains many more descriptions and discussions of implementation issues than evaluations of results for students. This may change as new evaluations appear, particularly in response to the evaluation requirements in STWOA. As Part II of this report has shown, however, the STW movement is diverse in its origins, purposes, and practices. A variety of STW models have been promoted by different public and private agencies. This makes it virtually impossible to answer the question whether the STW movement as a whole has produced positive results for students or young people. Even evaluating the effects of STWOA, which is only one piece of the STW movement, would be nearly impossible because localities and states are encouraged to use STWOA funds in many different ways.
The best we can do under these circumstances is try to learn from particular, focused programs or initiatives, and to draw lessons from their successes and failures that might provide examples to follow or pitfalls to avoid. The following section introduces the evaluation topic by reviewing what is necessary for an evaluation to be convincing. Section IV.2 then presents the results of studies that have appeared since our last review of this evaluation literature (Stern et al., 1995).