Museums often evaluate various aspects of their audiences' experiences, be it what they learn from a program or how they react to an exhibition. Each museum program or exhibition has its own set of goals, which can drive what an evaluator studies and how an evaluation evolves. When designing an evaluation, data collection methods are purposefully selected to provide the data needed to measure those goals and answer the evaluation questions at hand. This article provides an overview of the data collection methods commonly used in museum-related evaluations, informed by the work of the Building Informal Science Education (BISE) project.