As I teach a program evaluation course this semester, and as someone who began teaching program evaluation nearly 20 years ago (!), I find myself once again reflecting on how I define program evaluation and differentiate it from related fields and practices. My definitions and distinctions have certainly evolved over the years. In addition to commonly held definitions and distinctions, I have come to advocate that program evaluation requires big picture, evaluative questions to guide the work; data collection methods and sources chosen for the purpose of addressing those evaluation questions; and multiple sources of data. If these criteria are not met, it is not program evaluation. My evolving thoughts are captured in a document posted here. I would love your feedback!