This guide is meant to help the reader design evaluations that can answer these two questions. It was written for police officials and others who are responsible for evaluating the effectiveness of responses to problems. It assumes that the reader has a basic understanding of problem-oriented policing and the problem-solving process, including the SARA (Scanning, Analysis, Response, and Assessment) process. It is designed to be useful to readers who have no experience with evaluation and no background in evaluation and research methods. This guide also assumes that the reader has no outside assistance. Nevertheless, the reader should seek the advice and help of researchers with training and experience in evaluation, particularly if the problem being addressed is large and complex. An independent outside evaluator can be particularly useful if there is controversy over the usefulness of the response.