This guide is designed to introduce and explain the key concepts in outcome evaluation research in order to help practitioners distinguish between good and poor quality evaluation reports. The intent is to help practitioners 1) understand key evaluation terms and designs, and 2) recognize how to identify a well-written evaluation report. This guide does not explain how to identify evidence-based programs or “what works.” It is not intended to assist the reader with making overall judgments or determinations about specific programs or program types. More information than is found in one evaluation report is needed to identify whether a program is evidence-based. This guide provides the reader with the basic information needed to identify high quality evaluation reports.