Should learners reason
one step at a time?
Sarah Blissett
Deric Morrison
David McCarty
Matt Sibbald
I do not have an affiliation (financial or otherwise) with a
pharmaceutical, medical device or communications organization.
Je n’ai aucune affiliation (financière ou autre) avec une
entreprise pharmaceutique, un fabricant d’appareils
médicaux ou un cabinet de communication.
2
Cognitive load
•
Mental effort used in working memory
•
Working memory is limited
van Merrienboer JJG, Sweller. Medical Education 2010: 44: 85–93
Clinical decision making is
difficult
•
Making a diagnosis often requires integration of multiple
variables
•
Process can overwhelm working memory
Sweller et al. Educational Psychology Review, 10:251–296.
Schema use
•
Increased diagnostic accuracy
•
Lower cognitive load
Blissett et al. Medical Education, 46:815–822
Blissett et al. Advances in Health Sciences Education, 1-19
Coderre et al. Medical Education, 37:695–703.
Optimal schema layout?
Terminally branching schema
•
Single variable decisions
•
Optimize working memory
•
Perceptual error could result in
diagnostic error
Hybrid schema
•
Single variable decisions + chart
•
Limits of working memory
•
Allows cross checking to avoid
diagnostic error if perceptual
error made
The trade off
Hybrid
Terminally
branching
Research Question
Does schema layout impact diagnostic accuracy or cognitive
load?
Model
•
86 PGY1-3 Internal Medicine Residents at Western University
•
Murmur identification on Harvey, a cardiopulmonary simulator
86 PGY 1-3
Internal
Medicine
Residents
Randomized
Systolic
TB schema
86 PGY 1-3
Internal
Medicine
Residents
Randomized
Systolic
Hybrid schema
Diastolic
TB schema
Diastolic
Hybrid schema
Diagnostic accuracy
Perceptual error
Cognitive load
Systolic
TB schema
86 PGY 1-3
Internal
Medicine
Residents
Randomized
Systolic
Hybrid schema
Diastolic
TB schema
Diastolic
Hybrid schema
Diagnostic accuracy
Perceptual error
Cognitive load
86 PGY 1-3
Internal
Medicine
Residents
Randomized
Systolic
TB schema
Diastolic
Hybrid schema
Systolic
Hybrid schema
Diastolic
TB schema
Diastolic
TB schema
Systolic
Hybrid schema
Diastolic
Hybrid schema
Systolic
TB schema
Diagnostic accuracy
Perceptual error
Cognitive load
86 PGY 1-3
Internal
Medicine
Residents
Randomized
Diagnostic accuracy
Perceptual error
Cognitive load
Systolic
TB schema
Diastolic
Hybrid schema
Systolic
Hybrid schema
Diastolic
TB schema
Diastolic
TB schema
Systolic
Hybrid schema
Diastolic
Hybrid schema
Systolic
TB schema
Effect of schema organization
• Repeated measures MANOVA
• Main effect of schema type (p=0.004, ηp2 =0.15 )
• No significant effect of domain encountered first (p=0.763)
or within subjects (p=0.145)
• No significant effect of year of study (p=0.209)
Effect of schema organization
TB schema (95% CI)
Hybrid schema
(95% CI)
P-value
η p2
Diagnostic Accuracy
(%)
65
(58, 74)
55
(47, 63)
0.038
0.05
Perceptual error
0.61
(0.45, 0.77)
0.95
(0.78, 1.1)
0.002
0.115
Cognitive load
(1-7)
3.1
(2.9, 3.4)
3.5
(3.2, 3.8)
0.026
0.06
Terminally branching
schema:
diagnostic accuracy
errors, cognitive
load
Hybrid
Terminally
branching
Use of schemas may explain
results
Perspectives
•
Schema design
•
Clinical decision aids
•
Approach to complexity
Limitations
•
Model was inherently uncertain
•
Focused on schema use
Conclusion
Use of a terminally branching schema by intermediate learners
was associated with higher diagnostic accuracy and lower
cognitive load, suggesting intermediate learners should reason
“one step at a time”
Acknowledgements
•
Dr Matt Sibbald, David McCarty and Deric Morrison
•
Western University Department of Medicine
•
Centre for Education Research & Innovation
•
Royal College Robert Maudsley Fellowship for Studies in Medical
Education
Questions
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