Evaluation design for a community prevention trial. An environmental approach to reduce alcohol-involved trauma.

The Community Prevention Trial was 5-year effort to reduce alcohol-involved injuries and death through a comprehensive program of community awareness and policy activities. The three experimental communities were of approximately 100,000 population each (one in Northern California, one in Southern California, and one in South Carolina). Matched comparison communities were used for each experimental community. This article describes the evaluation approach used in a program that sought to change environmental factors not a specific population or target group. This approach demanded unique evaluation approaches for determining overall community aggregate effects, that is, distal outcomes, as well as changes in key mediating variables, that is, process effects. The problem of trending and lagged effects of community prevention programs are discussed.