Clinical decision making
Carl Thompson
UK, Centre for Evidence Based Nursing
Editor, Evidence Based Nursing
www.ebn.bmj.com
This session
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Integrating research evidence with
preferences and contextual information
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When should intuition and more
structured approaches be used?
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The ways people think and make choices
What’s right and wrong with clinical
experience?
Tools and techniques: decision analysis,
cognitive approaches
How do nurses (and doctors) think they think?
1. Make sense of
multiple cues
2. Diagnose or assess
3. Treat or intervene
4. Evaluate progress
5. Treat some more if
needed
Errr… start again…
How do they actually think?
The theory – cognitive continuum
Hamm,R (1988) in Dowie & Elstein, Clinical Judgement and decision
making, Cambridge University Press
Heuristics and Bias
Daniel Kahneman and Amos Tversky (d. 1996)
Tversky and Kahneman, Judgment Under Uncertainty:
Heuristics and Biases, Science (1974), Vol. 185,
pp 1124-1131
The Need to Assess Probabilities
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People need to make decisions constantly:
diagnosis and therapy
 Thus, people need to assess probabilities to classify
objects or predict various values, such as p
(DISEASE|SYMPTOMS)
 People employ heuristics to assess probabilities
 heuristics lead to significant biases,
CONSISTENTLY
 This observation leads to a descriptive, rather than a
normative, theory of human probability assessment
“Getting” healthcare is not easy
Pattern recognition is easier if you
have experience
Experience: A problem of perception
Slide from Slawson, Shaughnessy, Becker, 1999.
Do you see the Dalmation in
the picture?
Moral: Clinical experience
sometimes helps see,
sometimes prevents seeing
the right picture
Now that you see it, can you
try to not see it?
Moral: Experience can result
in ideas that are difficult to
change
One learns the basic patterns
One sees them in new situations.
Then one can see the pattern where before it
had been confusing.
Time and nursing decisions
Once every 30 seconds in critical care
(Bucknall, 2000)
 Circa 50 decisions every 8 hour shift in
Medical Admissions (Thompson et al.
2001 – 2005)
 5 judgement or decision challenges per
consult for health visitors.
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Remember uncertainty?
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How do we normally respond?
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Experiential/internal knowledge
Very limited textual information use and for certain
kinds of decisions (British National Formulary and
local protocols)
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90 hours of primary care = 1 telephone call
180 hours of acute care (1080 decisions) = local protocols
x4 times, BNF x50 times).
‘sophistication’ and technology doesn’t matter
(Randell et al. 2007).
Demography and biography poor predictors of use
The five classic decision pitfalls
 Representativeness
rate neglect
 Availability
 Overconfidence
 Confirmation
 Illusory correlations
and base
What can we do?
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Think about decision structure, time & visibility
Be aware of base rates
Consider whether information is truly relevant
and not just salient
Seek reasons why you may be wrong and
entertain alternatives
Ask questions that may disprove, rather than
confirm, your current hº
You are wrong more often than you think