Summary The purpose of this descriptive field study is to determine what factors influence staff nurses' decisions for non‐documentation of patients' response to analgesic administration. The study, based on Herbert Simon's descriptive model of decision making, has two components: (a) to determine staff nurses' perceptions of the factors that influence their documentation as well as how frequently they document analgesic administration and (b) to determine the actual frequency of nurses' documentation. Data collected from 67 staff nurses using a questionnaire designed for this study and through an audit of 65 patients' charts allowed comparison of nurses' perceptions with their actual practice. Analysis involved both quantitative and qualitative approaches. The results of the study have implications for nurse educators and nurse administrators.