The validation of nursing diagnostic concepts, interventions, and desired outcomes is necessary for the development of nursing science. The purpose of this article is to contribute to the development of more rigorous methods for research of nursing diagnoses. Methodologic problems and issues are discussed and illustrated in the context of a descriptive study of the nursing diagnoses of patients at a large long-term care facility. Issues surrounding the selection of setting and samples, the source and presentation of data collected, and methods used for data analysis and interpretation are described. The need for consistency among research questions, setting and sample, data collection methods, and data analysis and interpretation are emphasized. Researchers are encouraged to explicate the issues and decisions in nursing diagnosis research to encourage scholarly criticism and refinement by clinicians and scientists.