Factors associated with success in searching MEDLINE and applying evidence to answer clinical questions.

Abstract

This study sought to assess the ability of medical and nurse practitioner students to use MEDLINE to obtain evidence for answering clinical questions and to identify factors associated with the successful answering of questions. A convenience sample of medical and nurse practitioner students was recruited. After completing instruments measuring demographic variables, computer and searching attitudes and experience, and cognitive traits, the subjects were given a brief orientation to MEDLINE searching and the techniques of evidence-based medicine. The subjects were then given 5 questions (from a pool of 20) to answer in two sessions using the Ovid MEDLINE system and the Oregon Health & Science University library collection. Each question was answered using three possible responses that reflected the quality of the evidence. All actions capable of being logged by the Ovid system were captured. Statistical analysis was performed using a model based on generalized estimating equations. The relevance-based measures of recall and precision were measured by defining end queries and having relevance judgments made by physicians who were not associated with the study. Forty-five medical and 21 nurse practitioner students provided usable answers to 324 questions. The rate of correctness increased from 32.3 to 51.6 percent for medical students and from 31.7 to 34.7 percent for nurse practitioner students. Ability to answer questions correctly was most strongly associated with correctness of the answer before searching, user experience with MEDLINE features, the evidence-based medicine question type, and the spatial visualization score. The spatial visualization score showed multi-colinearity with student type (medical vs. nurse practitioner). Medical and nurse practitioner students obtained comparable recall and precision, neither of which was associated with correctness of the answer. Medical and nurse practitioner students in this study were at best moderately successful at answering clinical questions correctly with the assistance of literature searching. The results confirm the importance of evaluating both search ability and the ability to use the resulting information to accomplish a clinical task.