Teaching posttraining: influencing diagnostic strategy with instructions at test.

It is believed that medical diagnosis involves two complementary processes, analytic and similarity-based. There is considerable debate as to which of these processes defines diagnostic expertise and how best to teach clinical diagnosis and reduce diagnostic errors. The purpose of these studies is to document the use of these strategies in medical students. We shifted the balance in use of these processes and improved diagnostic accuracy with instructions given posttraining at the moment of diagnosis. Analytic processing reflecting the degree to which cases contain the diagnostic rules was indexed by the rate of accuracy on typical versus atypical cases (typicality effect). Similarity-based processing reflecting the degree to which cases resemble previously encountered cases was indexed by the rate of accuracy on similar versus dissimilar cases (similarity effect). Two studies are presented illustrating that diagnosis involves the coordination of analytic and similarity-based processes and that differential instruction given at test shifts the balance in the use of these processes. Study 1 illustrated that participants adopting an analytic strategy exhibit a larger effect of typicality. Participants adopting a similarity-based strategy exhibit a larger effect of similarity. The diagnostic approach of students given no instructions was predominantly analytic. Dual instructions in which participants first employed similarity-based processing followed by the application of rules improved overall accuracy. Study 2 investigated two versions of dual instructions and illustrated that assessing a case with the rules of diagnosis first may inhibit the subsequent use of similarity-based reasoning. The implications for diagnostic expertise and pedagogy are discussed.

Using comprehensive feature lists to bias medical diagnosis.

Clinicians routinely report fewer features in a case than they subsequently agree are present. The authors report studies that assess the effect of considering a more comprehensive description than physicians usually offer. These comprehensive descriptions were generated from photographs of dermatology and internal medicine and were complete and accurate. Groups of clinicians of varying expertise were asked to offer a diagnosis based solely on the comprehensive verbal description. This initial exercise decreased the subsequent diagnostic acumen of experienced participants with the photographs relative to a group that initially diagnosed from the photographs. Reasons that the initial consideration of a list of features, all of which are present in the photograph, would decrease diagnostic accuracy are discussed.

Validity of admissions measures in predicting performance outcomes: the contribution of cognitive and non-cognitive dimensions.

BACKGROUND: Admissions committees face the daunting task of selecting a small number of candidates who are most likely to succeed in medical school from a large pool of seemingly suitable applicants. While numerous studies have shown moderate correlations among measures of academic performance, predictors of the non-cognitive domain (e.g. interpersonal, communication, ethical) remain elusive, in part because of the absence of a sound criterion measure. PURPOSE: We examined the utility of several cognitive and non-cognitive criteria used in the admissions processes in predicting both cognitive and non-cognitive dimensions of the licencing examinations of the Medical Council of Canada (LMCC). METHODS: Predictors included: undergraduate GPA, undergraduate science GPA, an autobiographical letter, scores from a simulated tutorial, a personal interview and the MCAT. Of specific interest was the relation between measures of communication and problem-exploration skills as assessed during the admissions process and Part II of the LMCC Examination, a multi-station OSCE. RESULTS: Undergraduate GPAs were found to have the most utility in predicting both academic and clinical performance. Scores derived from the simulated tutorial did not predict future performance. The MCAT Verbal Reasoning score and the personal interview were found to be useful in predicting communication skills on the LMCC Part II. CONCLUSIONS: The results have implications for any school that uses the interview as an admissions tool.

Validity of admissions measures in predicting performance outcomes: a comparison of those who were and were not accepted at McMaster.

BACKGROUND: In typical validity studies, regression analyses are used to examine the relation between admissions measures and subsequent performance. This approach is problematic as it generally yields low correlation coefficients, which are difficult to interpret. Further, it leaves unanswered the question of how those applicants rejected by the process would fare had they been admitted. PURPOSE: This study examines the validity of the admissions measures used to assess non-cognitive qualities at McMaster's Medical School in a unique manner. METHODS: Three cohorts: (a) those offered an admission on the first round, (b) those offered an admission on the second round and (c) those rejected by McMaster, but accepted to another Canadian medical school were compared on admissions evaluations and licencing examination performance. RESULTS: The results indicate that although the scores of those who were offered an admission were significantly greater than those rejected by McMaster on each of the admission tools, licencing examination performance was comparable. CONCLUSIONS: These results are consistent with a previous regression-based validity study and indicate the need for closer examination of admissions tools.