What works best, for whom, and under what circumstances?

I guess that the conclusion should rephrase the question from "What will produce the greatest overall change?" to "What works best, for whom, and under what circumstances?". In other words, the focus shifts to seeking an understanding not only of the combination of circumstances where substantial gains have been achieved, but also where the innovation has been totally ineffective or possibly negative in outcome.

references:
Real World Research: A Resource for Social Scientists and Practitioner-Researchers, 2nd Edition. Colin Robson. (p.39)