This format can strengthen the intervention by empowering people to personally develop their own solutions to change their environment. Intervention science explores which components of programs are more effective and which programs work well in certain populations. For example, in a recent study, the riskiest people did not attend small group educational sessions. While most men attended outreach activities, few men were likely to attend safer sex workshops. Evaluation encourages critical thinking about the process of designing interventions, and should not only occur at the end of an intervention.
Good evaluation produces information about needs, service use patterns, impacts and outcomes.
It also gives a voice to clients' experiences, and allows service providers to learn about their programs so that they can make necessary changes to increase their effectiveness. An agency can hire a consultant or researcher for evaluation, or can conduct its own evaluation. For example, Tri-City Health Center in Fremont, CA surveyed suburban street youth to evaluate the effectiveness of their program of outreach and educational workshops. No one should need an advanced degree to understand prevention science. Several organizations exist to help translate and summarize research into understandable and usable forms.