1. Critical Thinking Richard M. Schwartzstein, MD
Executive Director, Carl J. Shapiro Institute for Education and Research
Faculty Associate Dean for Medical Education
Professor of Medicine
Harvard Medical School

2. Critical Thinking
Do you do it?

3. Critical Thinking
Do you do it?
Do you teach it?

4. Critical Thinking
Do you do it?
Do you teach it?
What is it?

5. Critical Thinking Do you do it? Do you teach it? What is it?
What is the relationship between “critical thinking” and “clinical reasoning?”

6. Who is this? (How do you know?)

7. Who is this?

8. Who is this? (How do you know?)
Political leader of the 20th century.
Mother was American, father was British
Lost election after leading his country to victory in war
Fancied whiskey

10. Case
A 60 year old man presents with a complaint of shortness of breath that has gradually worsened over 2 years. Now can only walk for 50 yards at which time he stops with a sensation of “suffocating” and “urge to breathe.” His wife notes “wheezing” when this happens.

11. Case, cont.
PH: asthma since childhood, hypertension for 30 years, mild diabetes, 30 pack year smoker
PE: obese. BP 160/90, HR 92, RR 16
Mild increase in AP diameter of chest. Lungs with mild decrease in air movement, I/E=1/1.5; JVP=10 cm. +S4. Abdomen benign. No edema.
Thoughts? What next?

12. Case, cont. Walk the patient:
After 50 yards, breathing starts to become labored, patient appears diaphoretic, chest exam: wheezes.
Diagnosis?

13. Cardiac Asthma Increased PCWP  interstitial edema, Dyspnea
Mechanical load
Hypoxemia
J-receptors
Vascular receptors
“urge to breathe,” “suffocating”

14. Diastolic Dysfunction
1/3 of cases of CHF are due primarily to diastolic dysfunction
Failure of LV to accommodate increased volume load
Symptoms often isolated to exercise

15. QUESTION
Is the patient an example to be learned or a problem to be solved?

16. QUESTION
Is the patient an example to be learned or a problem to be solved?
Pattern recognition = experience-based, non analytical reasoning
Norman G, Young M, Brooks L. Med Ed 2007

17. Primacy of Teaching Objectives
If “critical thinking” is one of our objectives, we have to understand what implications that has for our interactions with students and residents.

18. Critical Thinking Plan of Attack
Define the elements of critical thinking
Distinguish critical thinking from clinical reasoning
Delineate strategies for developing critical thinking in our learners.

19. Critical Thinking Plan of Attack
Define the elements of critical thinking
Distinguish critical thinking from clinical reasoning
Delineate strategies for developing critical thinking in our learners.
Caveat: this is a work in progress…

20. Hierarchy of Knowledge Bloom’sTaxonomy, 1956
Knowledge - What is the most common cause of...?
Understand - If you see this, what must you consider…?
Application - In this patient, what is causing…?
Analysis,synthesis,evaluation - critical thinking?

21. Revision of Bloom’s Taxonomy Anderson LW, Krathwohl DR (eds), 2001
Revision of Bloom’s Taxonomy Anderson LW, Krathwohl DR (eds), A taxonomy for learning, teaching and assessing: A revision of Bloom’s taxonomy of educational objectives. New York, Longman.

22. What is an expert? Mylopoulos M, Regehr G. Med Ed 2007
Expertise = Knowledge + Experience
Experts develop “rich and well organized resources…to effectively and efficiently solve routine problems of practice.”
“Only some experts go beyond routine competencies and display flexible, innovative abilities…in a process of extending their knowledge rather than applying it.”

23. Routine vs. Adaptive Expert Mylopoulos M, Regehr G. Med Ed 2007
Routine Expert
Novel problem adapt problem to the solution with which they are comfortable
Characterized by speed, accuracy, automaticity
Adaptive Expert
Use a new problem as a point of departure for exploration; expand knowledge and understanding
Characterized by innovation, creativity

24. Critical Thinking Is the KSA model appropriate?
Are there specific:
Knowledge/facts
Skills
Attitudes
…that must be acquired in order for the learner to become a critical thinker?

25. Knowledge Content learned in a conceptual framework
How do the facts fit together?
What are the underlying mechanisms?
What do you do when the patterns break down?
Content learned in a conceptual framework

26. Knowledge Content learned in a conceptual framework
Judge credibility of sources
From primary sources to “Google it…”
Primary sources
Study design
Appropriate population
Statistics
Secondary sources
Textbooks
Review articles
Evidence-based medicine

27. Knowledge Content learned in a conceptual framework
Judge credibility of sources
Bias and cognitive dispositions to respond
Availability bias- probability assigned based on ease of recall of specific examples
Confirmation bias - selectively accepting or ignoring data

28. Cognitive Dispositions to Respond Croskerry P, Acad Med, 2003, 78:775-780
Fatigue
Team factors
Affective state
Ambient conditions
Past experience
Patient factors

29. Skills Formulation of hypotheses How to pose questions
Going from the particular to the general
Are they testable?
Revising with new data
Identifying the key issues
Formulation of hypotheses

30. Skills
Symptoms link with physical findings? Lab data with symptoms and signs?
Finding common mechanisms
Formulation of hypotheses
Making logical connections between ideas

31. Skills Formulation of hypotheses
Making logical connections between ideas
Utilization of data
Sensitivity and specificity of tests
Pre and post-test probabilities
Red flags

32. Skills Formulation of hypotheses Cultural Gender
Making logical connections between ideas
Utilization of data
Identify assumptions
Cultural
Gender
Contextual, e.g., in our ED, upper lobe infiltrates are all TB

33. Attitudes Open mind - willingness to consider alternative explanations
Awareness of one’s own cognitive processes - what type of reasoning was I using? (metacognition)
Reflection - how did we go wrong? Where did we make a mistake?

34. Critical Thinking vs Clinical Reasoning

35. The Clinical Reasoning Paradigm
What do “experts” (routine experts?) do?
Content knowledge vs thought process
Mental representations of disease processes
Illness scripts (mini-patterns)
Semantic qualifiers (e.g., acute vs chronic, proximal vs distal)
Encapsulated knowledge (one type of knowledge embedded in other knowledge - basic mechs within clinical examples - example: “sepsis”)

36. How often do we need critical thinking in the clinical setting?
Bowen J, NEJM, 2006:355;
Pattern recognition (non-analytical thinking) is “essential to diagnostic expertise”
“Deliberative analytic reasoning is primary strategy when a case is complex…”

37. Clinical Reasoning and Critical Thinking

38. Clinical Reasoning My bias…
The 80/20 rule
80% of clinical medicine, pattern recognition works well.
20% of clinical medicine, to get it right, you need to apply the knowledge, skills, and attitudes of critical thinking.
The key - knowing into which group your patient fits.

39. Can we teach critical thinking?

40. Critical Thinking in College, Council for Learning Assessment (CLA), courtesy of Richard Hersh, EdD, lecture at HMS, Jan. 19, 2007

41. Some Strategies for Teaching Critical Thinking
Go back to the knowledge, skills, attributes
Be explicit that we are teaching critical thinking
Woven into teaching content
Separate teaching modules
Beware the hidden curriculum!!
A few thoughts from the literature (and my experience).

42. Concept Maps Guerrero, Acad Med 2001;76:385 Torre et al
Concept Maps Guerrero, Acad Med 2001;76:385 Torre et al., Am J Med 2006;119:903
Graphic devices to represent relationships between multiple concepts
Reinforce mechanistic thinking
Make links explicit

43. Higher Order Concepts Auclair F, BMC Medical Education 2007;7:16
32 third year students given complex CPC case (endocarditis) to analyze
12/32 made correct dx
Diagnostic accuracy  use of higher order concepts. Students who missed dx reported factual observations
19/25 students: given problem formulation (i.e, concept links) made dx
Problem not knowledge but moving from fact to concept

44. Case Conference Traditional 65 year old homeless man back pain
Hep C, spinal lymphoma
Later abn CXRMAC
Discuss: tests, meds, each disease in isolation

45. Case Conference Traditional 65 year old homeless man back pain
Hep C, spinal lymphoma
Later abn CXRMAC
Discuss: tests, meds, each disease in isolation
Critical thinking
65 year old homeless man back pain
Hep C, spinal lymphoma
Unifying mechs?
Abn CXRMAC
Discuss: make links -immune problemHIV

46. Model the Process Think out loud Discourage quick jumps to the dx
Force the student to assess her own thought process
Give frequent feedback
Test them on the process as well as the content

47. Final Thoughts…
There is more to be done to understand the elements of critical thinking.
If we are serious about this, we need to explicitly teach the process.
Critical thinking and clinical reasoning (as presently defined) are not the same.
Faculty development will be key.