Impacts of Four Title V, Section 510 Abstinence Education Programs. Sample Intake and Random Assignment


Sample intake took place near the beginning of three school years-1999-2000, 2000-2001, and 2001-2002. In each of these years, either program or school staff identified those youth who were eligible to participate in the programs. In the two non-elective programs  My Choice, My Future! and Teens in Control  eligible youth included all those in the targeted grade level (8th and 5th grades, respectively). In the elective programs  ReCapturing the Vision and FUPTP  eligible youth included all those in the targeted grade levels who had been identified by school or program staff as potential candidates. Once identified, eligible students were given a study consent form that notified parents of their child's eligibility for the program, explained the program and the evaluation, and described how selection for the program would take place through a lottery (random assignment).

In order for a student to be eligible both for the lottery and to participate in the evaluation, parents had to provide signed, active consent. In the two non-elective programs, parent consent rates were high, in excess of 90 percent (youth with parents not agreeing to participate were automatically placed in the classes that control group youth were to take). In the two other programs, parental consent rates could not be estimated because of their elective nature; however, there were few known cases of parents who wanted their child to participate in the program but opted out of the lottery because of the requirement to participate in the study.

In order to conduct the random assignment, lists of the eligible students who had active parental consent were sent to the evaluation team near the beginning of each school year and a random number generator was used to order the applicant pool. Once programs informed the evaluation team of the number of program slots available, the evaluation team released the names of students with that rank order or less in the assignment hierarchy. For example, in a program with 200 applicants and a capacity to serve 100 youth, the evaluation team released the names of the first 100 youth in the randomly ordered list of eligible applicants for inclusion in the program group. All students not selected for the program group formed an ordered "waitlist" and control group. In cases where it was necessary to maintain a minimum program enrollment, program vacancies were filled by releasing youth on the waitlist in the order of their original random number. Along with the original set of youth selected for the programs, all students selected from the waitlist to fill program vacancies became members of the study's program group regardless of whether they actually participated. All remaining students on the ordered waitlist formed the control group for the study.

In some instances, lists of eligible students were sent to the evaluation team in batches, leading to multiple rounds of random assignment within a school year. These multiple rounds of assignment, coupled with sample enrollment taking place over multiple school years, led to modest variation in the likelihood of students being selected for the program or control group. This variation in the selection probability was addressed in the analysis by using sample weights, as described below.

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