Suchergebnisse

A meta-analysis of substance abuse prevention studies revealed that the mean proportion of subjects retained dropped from 81.4% at 3-month to 67.5% at 3-year follow-ups. Time from pretest alone accounted for less than 5% of the variance. Other available predictors of retention were not significant. Researchers are encouraged to interpret their results in light of these normative data and to adopt second-effort strategies to reduce attrition.

It is not always possible, especially in large-scale evaluation research, to ensure that random assignment will produce groups that are comparable on any number of potentially important factors. Typically, gaining comparability has been achieved only at the expense of random assignment. A method is presented that allows multivariate comparability while making only minimal restrictions on randomization. The procedure is demonstrated in the context of assigning 63 aggregated units (schools) to 28 experimental and control conditions. Good comparability of groups for all primary main effects and interactions was venfied for 15 individual variables.

This study evaluated the relationship between level of program implementation and change in adolescent drug use behavior in the Midwestern Prevention Project (MPP), a school- and community-based program for drug abuse prevention. Trained teachers implemented the pro gram with transition year students. Implementation was measured by teacher self-report and validated by research staff reports. Adolescent drug use was measured by student self-report; an expired air measure of smoking was used to increase the accuracy of self-reported drug use. Regression analyses were used to evaluate adherence; exposure, or amount of implementation; and reinvention. Results showed that all schools assigned to the program condition adhered to the research by implementing the program. Exposure had a significant effect on minimizing the increase in drug use from baseline to one year. Exposure also had a larger magnitude of intervention effect than experimental group assignment. Reinvention did not affect drug use. Results are discussed in terms of research assumptions about quality of program implementation, and possible school-level predictors of implementation.