Critical Thinking

Richard M. Schwartzstein, MDExecutive Director, Carl J. Shapiro Institute

for Education and Research

Faculty Associate Dean for Medical Education

Professor of Medicine

Harvard Medical School

Critical Thinking

• Do you do it?

Critical Thinking

• Do you do it?

• Do you teach it?

Critical Thinking

• Do you do it?

• Do you teach it?

• What is it?

Critical Thinking

• Do you do it?

• Do you teach it?

• What is it?

• What is the relationship between “critical thinking” and “clinical reasoning?”

Who is this?(How do you know?)

Who is this?

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

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.

Case, cont.

• PH: asthma since childhood, hypertension for 30 years, mild diabetes, 30 pack year smoker

• PE: obese. BP 160/90, HR 92, RR 16Mild 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?

Case, cont.

• Walk the patient:

After 50 yards, breathing starts to become labored, patient appears diaphoretic, chest exam: wheezes.

Diagnosis?

Cardiac Asthma• Increased PCWP

interstitial edema, • Dyspnea

– Mechanical load– Hypoxemia– J-receptors– Vascular

receptors– “urge to breathe,”

“suffocating”

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

QUESTION

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

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

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.

Critical ThinkingPlan of Attack

• Define the elements of critical thinking

• Distinguish critical thinking from clinical reasoning

• Delineate strategies for developing critical thinking in our learners.

Critical ThinkingPlan 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…

Hierarchy of KnowledgeBloom’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?

Revision of Bloom’s TaxonomyAnderson LW, Krathwohl DR (eds), 2001. A taxonomy for learning, teaching and assessing: A revision of Bloom’s

taxonomy of educational objectives. New York, Longman.

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.”

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

Critical ThinkingIs 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?

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?

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

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

Cognitive Dispositions to Respond

Croskerry P, Acad Med, 2003, 78:775-780

• Fatigue• Team factors• Affective state• Ambient conditions• Past experience• Patient factors

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

Skills

• Formulation of hypotheses

• Making logical connections between ideas

• Symptoms link with physical findings? Lab data with symptoms and signs?

• Finding common mechanisms

Skills

• Formulation of hypotheses

• Making logical connections between ideas

• Utilization of data

• Sensitivity and specificity of tests

• Pre and post-test probabilities

• Red flags

Skills

• Formulation of hypotheses

• Making logical connections between ideas

• Utilization of data• Identify

assumptions

• Cultural• Gender• Contextual,

e.g., in our ED, upper lobe infiltrates are all TB

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?

Critical Thinking vs Clinical Reasoning

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”)

How often do we need critical thinking in the clinical setting?

• Bowen J, NEJM, 2006:355;2217-2225– Pattern recognition

(non-analytical thinking) is “essential to diagnostic expertise”

– “Deliberative analytic reasoning is primary strategy when a case is complex…”

Clinical Reasoning and Critical Thinking

Clinical ReasoningMy 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.

Can we teach critical thinking?

Critical Thinking in College, Council for Learning Assessment (CLA), courtesy of

Richard Hersh, EdD, lecture at HMS, Jan. 19, 2007

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).

Concept MapsGuerrero, 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

Higher Order ConceptsAuclair 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

Case Conference

Traditional• 65 year old homeless

man back pain• Hep C, spinal

lymphoma• Later abn CXRMAC• Discuss: tests, meds,

each disease in isolation

Case ConferenceTraditional• 65 year old

homeless man back pain

• Hep C, spinal lymphoma

• Later abn CXRMAC

• Discuss: tests, meds, each disease in isolation

Critical thinking• 65 year old

homeless man back pain

• Hep C, spinal lymphoma

• Unifying mechs? • Abn CXRMAC• Discuss: make links

-immune problemHIV

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

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.