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The role of strategy and redundancy in diagnostic reasoning.

Bloch RF, Hofer D, Feller S, Hodel M - BMC Med Educ (2003)

Bottom Line: For discordant cases, refutation testing occurs significantly in 6th year students (p < 0.001) and residents (p < 0.01), but not in psychology or 3rd year students.Knowledge and practice are both important for diagnostic success.For complex diagnostic situations reasoning components employing redundancy seem more essential than those using strategy.

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Affiliation: Institute for Medical Education (IAWF), Faculty of Medicine, University of Bern, Inselspital 37a, 3010 Bern, Switzerland. bloch@iae.unibe.ch

ABSTRACT

Background: Diagnostic reasoning is a key competence of physicians. We explored the effects of knowledge, practice and additional clinical information on strategy, redundancy and accuracy of diagnosing a peripheral neurological defect in the hand based on sensory examination.

Method: Using an interactive computer simulation that includes 21 unique cases with seven sensory loss patterns and either concordant, neutral or discordant textual information, 21 3rd year medical students, 21 6th year and 21 senior neurology residents each examined 15 cases over the course of one session. An additional 23 psychology students examined 24 cases over two sessions, 12 cases per session. Subjects also took a seven-item MCQ exam of seven classical patterns presented visually.

Results: Knowledge of sensory patterns and diagnostic accuracy are highly correlated within groups (R2 = 0.64). The total amount of information gathered for incorrect diagnoses is no lower than that for correct diagnoses. Residents require significantly fewer tests than either psychology or 6th year students, who in turn require fewer than the 3rd year students (p < 0.001). The diagnostic accuracy of subjects is affected both by level of training (p < 0.001) and concordance of clinical information (p < 0.001). For discordant cases, refutation testing occurs significantly in 6th year students (p < 0.001) and residents (p < 0.01), but not in psychology or 3rd year students. Conversely, there is a stable 55% excess of confirmatory testing, independent of training or concordance.

Conclusions: Knowledge and practice are both important for diagnostic success. For complex diagnostic situations reasoning components employing redundancy seem more essential than those using strategy.

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Related in: MedlinePlus

Example of one illustrative sequence. For all diagnoses except D4 the plausibilities successively disappear. Correspondingly, the entropy falls from 1.0 to 0.0. After seven tests total certainty exists.
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Figure 6: Example of one illustrative sequence. For all diagnoses except D4 the plausibilities successively disappear. Correspondingly, the entropy falls from 1.0 to 0.0. After seven tests total certainty exists.

Mentions: The faster a subject accumulates sufficient information to arrive at the correct diagnosis, the more efficient is his diagnostic strategy. Quantitatively, this is indicated by a smaller area under the entropy/number-of-test curve (Figure 6).


The role of strategy and redundancy in diagnostic reasoning.

Bloch RF, Hofer D, Feller S, Hodel M - BMC Med Educ (2003)

Example of one illustrative sequence. For all diagnoses except D4 the plausibilities successively disappear. Correspondingly, the entropy falls from 1.0 to 0.0. After seven tests total certainty exists.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC149359&req=5

Figure 6: Example of one illustrative sequence. For all diagnoses except D4 the plausibilities successively disappear. Correspondingly, the entropy falls from 1.0 to 0.0. After seven tests total certainty exists.
Mentions: The faster a subject accumulates sufficient information to arrive at the correct diagnosis, the more efficient is his diagnostic strategy. Quantitatively, this is indicated by a smaller area under the entropy/number-of-test curve (Figure 6).

Bottom Line: For discordant cases, refutation testing occurs significantly in 6th year students (p < 0.001) and residents (p < 0.01), but not in psychology or 3rd year students.Knowledge and practice are both important for diagnostic success.For complex diagnostic situations reasoning components employing redundancy seem more essential than those using strategy.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Medical Education (IAWF), Faculty of Medicine, University of Bern, Inselspital 37a, 3010 Bern, Switzerland. bloch@iae.unibe.ch

ABSTRACT

Background: Diagnostic reasoning is a key competence of physicians. We explored the effects of knowledge, practice and additional clinical information on strategy, redundancy and accuracy of diagnosing a peripheral neurological defect in the hand based on sensory examination.

Method: Using an interactive computer simulation that includes 21 unique cases with seven sensory loss patterns and either concordant, neutral or discordant textual information, 21 3rd year medical students, 21 6th year and 21 senior neurology residents each examined 15 cases over the course of one session. An additional 23 psychology students examined 24 cases over two sessions, 12 cases per session. Subjects also took a seven-item MCQ exam of seven classical patterns presented visually.

Results: Knowledge of sensory patterns and diagnostic accuracy are highly correlated within groups (R2 = 0.64). The total amount of information gathered for incorrect diagnoses is no lower than that for correct diagnoses. Residents require significantly fewer tests than either psychology or 6th year students, who in turn require fewer than the 3rd year students (p < 0.001). The diagnostic accuracy of subjects is affected both by level of training (p < 0.001) and concordance of clinical information (p < 0.001). For discordant cases, refutation testing occurs significantly in 6th year students (p < 0.001) and residents (p < 0.01), but not in psychology or 3rd year students. Conversely, there is a stable 55% excess of confirmatory testing, independent of training or concordance.

Conclusions: Knowledge and practice are both important for diagnostic success. For complex diagnostic situations reasoning components employing redundancy seem more essential than those using strategy.

Show MeSH
Related in: MedlinePlus