The influence of experience on community health nurses' use of the similarity heuristic in diagnostic reasoning.

This study explored the diagnostic reasoning of community health nurses, examining the association between nursing experience and use of the cognitive heuristic similarity. Two types of similarity reasoning were examined, similarity to a single prototype (SSP) and similarity to a population prototype (SPP). The hypothesis of the study, derived from heuristics theory and ACT theory predicted that experts would be more likely to make diagnoses by similarity assessment than less experienced nurses. A random sample of 214 community health nurses was studied. Each subject completed eight diagnostic problems included in the Clinical Inference Questionnaire (CIQ) that was developed for this study to measure judging by similarity. Most of the nurses in this study, regardless of experience, used similarity assessment as a basis for some diagnoses. Experts were more likely than less experienced nurses to judge by similarity in population prototype problems but not in single prototype problems. These findings suggest that the diagnostic process includes similarity reasoning and imply that this process cannot be well understood without further exploration of the role of cognitive heuristics.