In this article, I attempt to merge two themes. First, there is often a large gap between high hopes about impacts of policies or programs and the demonstrated results. I describe four keys/threats to success in any social problem area: theory, implementation, evaluation, and resource/system support. Second, I present theory and research from over 30 years of work on participation, conducted by my colleagues and myself that can illuminate and be illuminated by theory, implementation, evaluation, and resource/system support. I offer ideas for solutions that increase the probability of success. I conclude with the need to have high hopes tempered by theory and research to develop realistically ambitious solutions to social problems.