Nurses frequently make treatment decisions in the care of children who may be experiencing pain. Undertreatment, ineffective treatment and inappropriate treatment of pain in children are common occurrences. This research investigates, through the use of a multiple case study design, how nurses make decisions regarding pain when caring for children. The specific aims of the study are 1) To describe how nurses in two sites care for children in pain: the clusters of cues they use in making a clinical diagnosis of pain, the treatment modalities they select, and the evaluation strategies they use to determine the effectiveness of the treatment, 2) To identify patterns of clinical decision-making that are used by nurses in the care of children experiencing pain, 3) To compare the patterns of the clinical decision-making process that occurred within a case study, across case studies in each site, and across two sites, 4) To explain the similarities and dissimilarities in the patterns of clinical decision- making processes that occurred within a case study, across case studies, and across sites, and 5) To derive and conceptual model(s) that explain (s) the clinical decision-making process nurses use when caring for children who may have pain. Sixty nurses will be recruited for the study with subjects being purposively selected according to replication logic (i.e. to represent either literal or theoretical replication). Data will be collected using multiple data collection methods: interviews, observation, questionnaires, and retrieval from documents. Both qualitative and quantitative analyses will be undertaken to describe patterns of clinical decision-making processes. Case reports will be written for each case study. A summary report of all the case studies will contain the findings from the cross-case and cross-site analyses as well as recommendations for further research. The study is expected to be relevant for all nurses who work with children in pain to the extent that it illuminates the process of clinical decision-making