Giving learners the best of both worlds: do clinical teachers need to guard against teaching pattern recognition to novices?
OBJECTIVE
There has been much debate in the medical education literature regarding the extent to which feature-driven and nonanalytic (similarity-based) reasoning strategies define expertise, but the relative value of teaching these strategies, together or in isolation, remains uncertain. The purpose of this study was to compare the diagnostic accuracy achieved upon receiving instruction to use each strategy in isolation to that of a combined approach.


METHODS
In 2003-04, 48 undergraduate psychology students from McMaster University in Ontario, Canada, were taught to diagnose ten cardiac disorders (including normal) via electrocardiogram (ECG) presentation. Twelve students were instructed to carefully identify all features present before assigning a diagnosis (feature first). Twelve were given the same instruction with notice that some test ECGs had been seen during training (implicit combined). Twelve were simply instructed to trust familiarity and diagnose based on this impression (similarity-based). Finally, 12 students were given feature first and similarity-based instructions in combination (explicit combined).


RESULTS
No difference in diagnostic accuracy was observed between the groups given the feature first (42%) and first impression (41%) instructions (p > .4), but the groups instructed to use both strategies (explicitly or implicitly) performed significantly better (56% and 53%, respectively; p < .01).


CONCLUSIONS
The results support an additive model of clinical reasoning in which instructions to be feature oriented and to trust similarity improve performance in novice diagnosticians.
Ark
Tavinder K
TK
Program for Educational Research and Development, MDCL 3522, McMaster University, 1200 Main Street West, Hamilton, Ontario, Canada, L8N 3Z5.
Brooks
Lee R
LR
Eva
Kevin W
KW
D000328:Adult; D015510:Clinical Medicine / Q000193:education*; D003071:Cognition; D003937:Diagnosis, Differential; D004501:Education, Medical / Q000639:trends*; D004562:Electrocardiography; D006331:Heart Diseases / Q000175:diagnosis; D006801:Humans; D046709:Pattern Recognition, Physiological; D011584:Psychology / Q000193:education*