CIPP was instrumental in showing evaluators and program managers that they need not wait until an activity or program has run its course before evaluating it. In fact, evaluation can begin when ideas for programs are first being discussed. Because of lost opportunities and heavy resource investment, evaluation is generally least effective at the end of a developing program. But today’s emphasis on outcomes and impact has reduced evaluation's role at the planning stages.
Nevertheless, particularly when purposes are formative, examining issues concerning context, input, and process can be helpful in identifying problems before they have grown and in suggesting solutions that will work better at achieving outcomes. For example, process studies may identify ways that teachers or other program deliverers are implementing a program, such as deviating from the intended activities because they are not working or are not feasible. Discovering these new methods, modifying the program model to conform to the new methods, and training others in them can help achieve program success.