Testing components is also necessary in preventive interventions that are designed to be flexible, so that the program can be tailored to the specific needs of the participants. Fast Track, for example (see Box 6-9), was a randomized trial aimed at preventing the consequences of aggressive behavior from first grade through high school (Conduct Problems Prevention Research Group, 1992, 1999a, 1999b). Over the course of the 10-year study, each participant in the intervention condition received specific program components that were deemed most appropriate based on his or her risks and protective factors at a given point in life. By the end of the study, the set of interventions and their dosages or durations differed substantially from person to person. Analytical techniques are available to disentangle some of the effects of dosage from different levels of need, but the use of designs, especially with multiple levels of randomization, may provide clearer insight into the effects of the intervention components (Murphy, van der Laan, et al., 2001; Murphy, 2003; Collins, Murphy, and Strecher, 2007).
There is also interest in testing whether small, relatively simple elements of a prevention program can be successfully applied in different contexts. For example, implementation of the Good Behavior Game in first and second grade, which gave teachers an extensive period of training and supervision and included the creation of a support structure in the school and the district, was found to have long-term benefits for high-risk boys (Kellam, Brown, et al., 2008; Petras, Kellam, et al., 2008). In an effort to provide this intervention at reduced cost, others have attempted to implement the Good Behavior Game intervention using much less training and system-level support (Embry, 2004). Because the training received as part of one intervention becomes part of a teacher’s toolkit, it would be useful to evaluate the subsequent effects of the differences in teachers’ training and support in conjunction with the Good Behavior Game on levels of aggressive behavior in their students. Program components can be tested by themselves by randomizing which teachers, or other such intervention agents, are to receive no training, low training, or high training.
The Internet presents new opportunities to deliver preventive interventions to a diverse and expanding audience and to test the interventions in large randomized trials. With the delivery of a prevention program through the web, the opportunity exists to test new or refined components using