An Innovative and Unconventional Approach to Program-Evaluation in the Field of Substance-Abuse Prevention - A Threshold-Gating Approach Using Single System Evaluation Designs

The main focus of this paper is directed to three fronts. First, we introduce an innovative alternative to program evaluation that we call the ''threshold-gating approach.'' This approach is suggested as a viable alternative to the problems inherent in the evaluation of large-scale social experimentation. Nevertheless, this approach offers a sufficient number of logical nets to negate alternative generalizations. Second, an effort is made to provide alternative evaluation designs that could be used to determine the treatment effect of intervention in the absence of control groups where the socioeconomic and environmental context of the program remains dynamic but somewhat stable. In the evaluation of alcohol, tobacco, and other drug prevention programs, there is an increasing demand for this type of evaluation design. Collectively, these designs are referred to as a single system evaluation design. They include longitudinal designs, individual growth curve models, within-experimental control design, meta-analytic control design, small focus group evaluation design, multiple time series control method, retrospective pretest design, 1/3 s-rule, etc. Finally, this paper stipulates some important evaluation guidelines that have utility in determining ''treatment'' outcome. These include rules to be applied when selecting criterion variables, respondent exclusionary rules based on statistical properties of the regression-toward-the-mean and scale limitations inherent in all evaluation instruments, as well as some additional rules that may be applied in making statistical decisions.