Qualitative evaluation studies can differ markedly from quantitative ones in both purpose and method and therefore must be understood and evaluated on their own terms. This article defines qualitative evaluation research and describes key parameters of quality to be considered when conducting and evaluating these studies in terms that take their epistemological assumptions and unique methods into account. Dimensions discussed include clarity in the research question, identifying the epistemological framework, using theory and prior knowledge effectively, addressing ethical issues, documenting all aspects of the study method, ensuring trustworthiness of the data, and communicating findings effectively.