As noted in Chapter II, a sizeable proportion of youth assigned to the program group in the two sites with elective programs, ReCapturing the Vision and FUPTP, did not participate in any program classes or other services (35 percent and 43 percent, respectively). To address this program nonparticipation, impact estimates are presented two ways in the report. The first is for the full program group. This estimate reflects the average effect of having the opportunity to participate in the program, whether or not the youth actually chose to participate. These estimates are featured throughout the report since it generalizes to the youth who were made eligible for the programs. The second is for only those youth in the program group who actually participated. These estimates are derived following the procedure developed by Bloom (1984), which divides the full-sample estimate by the participation rate. Because the standard errors and significance levels associated with the participant-only estimates are roughly similar to those for the full program group, impact estimates found not statistically significant for the full program group are typically not statistically significant for the participants either. As a result, the conclusions from the study do not differ substantively when based on one set of measures or the other.
Crossover of control group youth into the program group was rare, including at most 5 percent of the sample. For this reason, the report does not present estimates that account for crossover. To the extent that youth who did cross over experienced positive benefits from participating in the programs, the impact estimates reported are understated slightly.