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 in troduce an innovative alternative to program evaluation that we call t he ''threshold-gating approach.'' This approach is suggested as a viab le alternative to the problems inherent in the evaluation of large-sca le social experimentation. Nevertheless, this approach offers a suffic ient number of logical nets to negate alternative generalizations. Sec ond, 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 c ontext of the program remains dynamic but somewhat stable. In the eval uation of alcohol, tobacco, and other drug prevention programs, there is an increasing demand for this type of evaluation design. Collective ly, these designs are referred to as a single system evaluation design . They include longitudinal designs, individual growth curve models, w ithin-experimental control design, meta-analytic control design, small focus group evaluation design, multiple time series control method, r etrospective pretest design, 1/3 s-rule, etc. Finally, this paper stip ulates some important evaluation guidelines that have utility in deter mining ''treatment'' outcome. These include rules to be applied when s electing criterion variables, respondent exclusionary rules based on s tatistical properties of the regression-toward-the-mean and scale limi tations inherent in all evaluation instruments, as well as some additi onal rules that may be applied in making statistical decisions.