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ClinicalReasoning2:Howdoctorsthink
DrNicolaCooperMBChBFAcadMEdFRCPEFRACPConsultantPhysician&HonoraryClinicalAssociateProfessor
Therearetwoclinicalreasoningworkshopsinthefirstyear.
Bytheendofthis sessionyoushould:
• Knowwhat‘reasoning’means
• Understandwhatismeantby‘rationality’inmedicine
• Beabletodescribedualprocesstheory
• Knowwhatcognitivebiasesareandtheirroleindiagnosis
Learningobjectives
‘Medicaleducationdoesagoodjobofimpartingthenecessaryknowledgetowould-bepractitionersbuthasbeenlesseffectiveataddressingthequestionofhowtheyshouldsubsequentlythinkabouttheknowledgetheyhavepainstakinglyacquired.’
Croskerry,P.Therationaldiagnostician.In:CroskerryP,CosbyK,GraberMLandSingh
Whatismeantby‘clinicalreasoning’?
‘Aclinician’sabilitytomakedecisions,oftenwithothers,basedontheavailableclinicalinformation,whichincludeshistory(sometimesfrommultiplesources),physicalexaminationfindingsandtestresults– againstabackdropofuncertainty.[It]alsoincludeschoosingappropriatetreatments(ornotreatmentatall)anddecision-makingwithpatientsand/ortheircarers.’
CooperN&FrainJ[Eds].ABCofClinicalReasoning.Wiley,2016.
Whatisclinicalreasoning?
Inalldefinitionsintheliterature,several‘components’(i.e.elementsofalargerwhole)oftheclinicalreasoningprocessaredescribed:
• History• Physicalexamination• Useandinterpretationofdiagnostictests• Reasoning/rationality• Shareddecisionmaking(withpatients,carers,teams,guidelinesetc.)
• Formalandexperientialknowledgeofmedicine
Whatisclinicalreasoning?
Whydoesclinicalreasoningmatter?
Thescaleofdiagnosticerror
• 1in10diagnosesareincorrect
• Diagnosticerrorcausessignificantharm
• Diagnosticerroraccountsfor40,000– 80,000deathsannuallyintheUS,somewherebetweenbreastcanceranddiabetes
• Chancesare,wewillallexperienceadiagnosticerrorinourlifetime
USInstituteofMedicine.(2013).25-yearsummaryofUSmalpracticeclaimsfordiagnosticerrors1986-2010:ananalysisfromtheNationalPractitionerDataBank.BMJQual Saf;22(8):672-680
Results-‘System-relatedfactorscontributedtodiagnosticerrorin65%ofthecasesandcognitivefactorsin74%… themostcommoncognitivefactorsinvolvedfaultysynthesis.’
SherbinoJ&NormanGR.(2014).AcademicEmergencyMedicine;21(8):931-933.
‘Theprevailingopinionthatdiagnosticerrorisacognitiveprocessingerror… isincorrect.Thisperspectivepresupposesthatalloftheavailableknowledgeispresent… Incontrast,adiagnosticerrormayreflectnotaprocessingerror,butanincompleteknowledgebaseorinadequateexperience.’
Thecomponentsofclinicalreasoning
Basic science
& clinical medicine
Shared decision-making*
Evidence-based physical
examination
Evidence-basedhistory
Reasoning/rationality
Use and interpretation of diagnostic
tests
Clinical Reasoning
Whydoes‘reasoning’mean?
Reasoningisaphilosophicalterm
‘Touseone'smindtoformopinionsandjudgements,reachlogicalconclusions,deduce,etc.’
Itincludesformallogicalreasoning(e.g.deduction,induction,abduction)andinformalintuitivereasoning.
TheChambersDictionary13th Ed.Chambers,2014.
Whatismeantby‘rationality’inmedicine?
CroskerryP.Therationaldiagnostician.In:CroskerryP,CosbyK,GraberM&SinghH.[Eds].Diagnosis:interpretingtheshadows.CRCPress,2017.
Themajorcomponentsofrationalityinmedicine
Individualcharacteristics
Peoplehavedifferentthinkingdispositions:
• Tendencytoseekinformation• Tendencytolookforevidence• Tendencytoanalyse,weighthingsup,beforedeciding• Healthyskepticism• Awarenessofcontext• Tendencytoreflect/thinkabouttheirownthinking
Experienceandthecognitivemiserfunction
Source:NationalGeographicChannel.
Dualprocesstheory
Clinicalreasoningandmemory
EvaKetal.(2002).Expert/novicedifferencesinmemory:areformulation.Teachingandlearninginmedicine;14:257-263SchmidtHG&Boshuizen HPA.(1993).Ontheoriginofintermediateeffectsinclinicalcaserecall.Memoryandcognition;21:338-351
Abatandaballcost£1.10intotal.Thebatcosts£1morethantheball.Howmuchdoestheballcost?
KahnemanD.Thinking,fastandslow.AllenLane,2011.
Dualprocesstheory
System1• Intuitive,heuristic(patterns)• Automatic,subconscious• Fast,effortless• Low/variablereliability• Vulnerabletoerror• Highlyaffectedbycontext• Highemotionalinvolvement
System2• Analytical,systematic• Deliberate,conscious• Slow,effortful• High/consistentreliability• Lesspronetoerror• Lessaffectedbycontext• Lowemotionalinvolvement• Requiresaccesstoworkingmemory
Dualprocesstheory
Adapted from Croskerry P. A universal model of diagnostic reasoning. Academic Medicine 2009; 84(8): 1022-1028.
Cognitivebiasesaresubconsciouserrorsinperception,judgementandinterpretationofinformation,andtheyareprevalentineverydaylife:'Toerrishuman'.
Cognitive biases
Socialbiases
Memorybiases
Decisionmakingbiases
Probability/beliefbiases
Casehistory(seeworksheet)
Spotthecognitivebiasesatplay
Subconsciouserrors
AnchoringWhenwefixonaparticularbitofinformation,leadingustothinkinaconstrainedway
ConfirmationbiasTendencytolookforconfirmingevidencetosupportourinitialhypothesisratherthanlookingfordisconfirmingevidencetorefuteit
DiagnosticmomentumTendencyforaparticulardiagnosistostickdespitelackofsupportingevidence
SearchsatisficingFromthewords‘satisfy’ and‘sufficient’ - whenwestopsearchingbecausewehavefoundsomethingthatfitsorisconvenient,insteadofsystematicallylookingforthebestalternative
Diagnosticmomentum
• Tendencyforaparticulardiagnosistostickdespitelackofsupportingevidence
• ‘Likeaboulderrollingdownamountain,thediagnosisgathersmomentum,crushingallelseinitspath’
• Usuallyinvolvesseveralintermediaries,includingthepatient
•Oftenstartsasanopinion,notnecessarilymedical,andpassedwithincreasingcertaintyfromonepersontothenext
•Diagnosticlabelsbecomeparticularly‘sticky’ onceapatienthasbeenseenbyaconsultant
Wife:‘I’mworried
you’rehavinga
heartattack’
Patient:‘ItfeelslikeI’mhavinga
heartattack…’
Paramedic:‘52-year-oldmalewithpossibleACS.’
Nurse:‘Youknowthatman
with?ACSincubicle12?’
Doctor:Documents‘possibleACS’innotes…
‘Biasshouldbeconsideredanormaloperatingcharacteristicofthehumanbrain– biasesareeverywhereandhavethepotentialtoinfluencealmosteverydecisionwemake.’
CroskerryP.Bias:anormaloperatingcharacteristicofthediagnosingbrain.Diagnosis2014;1:23-7
DIAGNOSTICERROR
EXTERNALFACTORSDistractionsCognitiveloadDecisiondensityTimepressures
AmbientconditionsInsufficientdataTeamfactorsPatientfactorsPoorfeedback
INTERNALFACTORSKnowledgeTraining
Beliefs/valuesEmotions
Sleep/fatigueStress
Affective/physicalillness
OverconfidenceRisk-takingbehaviour
COGNITIVEBIASES/ERRORSUseofintuitive
(System1)decision-makingprocesses
Factorsincreasingthelikelihoodofdiagnosticerror
Cognitivebiasesanderrors:whatcanwedoaboutit?
Results-‘System-relatedfactorscontributedtodiagnosticerrorin65%ofthecasesandcognitivefactorsin74%… themostcommoncognitivefactorsinvolvedfaultysynthesis.’
SherbinoJ&NormanGR.(2014).AcademicEmergencyMedicine;21(8):931-933.
‘Theprevailingopinionthatdiagnosticerrorisacognitiveprocessingerror… isincorrect.Thisperspectivepresupposesthatalloftheavailableknowledgeispresent… Incontrast,adiagnosticerrormayreflectnotaprocessingerror,butanincompleteknowledgebaseorinadequateexperience.’
Reflection is consistently beneficial
230 Evans, Stanovich
dual-process views, Newstead (2000) argued that “Epstein, Pacini, Denes-Raj, and Heier (1996) found that supersti-tious and categorical thinking, which might be supposed to be part of System 1, produced no significant correla-tions, either positive or negative, with Faith in Intuition (System 1)” (p. 690). But superstitious thinking signals a mode of thought, not a type—and this disposition is not at all an indicator of the functioning of Type 1 pro-cessing. It is a thinking disposition involving epistemic regulation—a Type 2 function.
Modes of processing—more commonly termed think-ing dispositions—are well represented in Stanovich’s (2009a, 2009b, 2011) tripartite model of mind displayed in its simplest form in Figure 1. In the spirit of Dennett’s (1996) book Kinds of Minds, the set of autonomous sys-tems (the source of Type 1 processing) is labeled as the autonomous mind, the algorithmic level of Type 2 pro-cessing the algorithmic mind, and the reflective level of Type 2 processing the reflective mind. Dennett’s “kinds of minds” terminology refers to hierarchies of control rather than separate systems. Two levels of control are associated with Type 2 processing and one with Type 1 processing. The autonomous set of systems (TASS) will implement their short-leashed goals unless overridden by an inhibitory mechanism of the algorithmic mind. But override itself is initiated by higher level control. That is, the algorithmic level is subordinate to higher level goal states and epistemic thinking dispositions. These goal states and epistemic dispositions exist at what might be termed the reflective level of processing—a level
containing control states that regulate behavior at a high level of generality. Such high-level goal states are com-mon in the intelligent agents built by artificial intelligence researchers (A. Sloman & Chrisley, 2003).
The difference between the algorithmic mind and the reflective mind is captured in the well-established distinc-tion in the measurement of individual differences between cognitive ability and thinking dispositions (and repre-sented in Fig. 1). The former are measures of the ability of the algorithmic mind to sustain decoupled representa-tions (for purposes of inhibition or simulation, see Stanovich, 2011). In contrast, thinking dispositions are measures of the higher level regulatory states of the reflec-tive mind: the tendency to collect information before making up one’s mind, the tendency to seek various points of view before coming to a conclusion, the disposi-tion to think extensively about a problem before respond-ing, the tendency to calibrate the degree of strength of one’s opinion to the degree of evidence available, the tendency to think about future consequences before tak-ing action, and the tendency to explicitly weigh pluses and minuses of situations before making a decision.
Thus, thinking disposition measures are telling us about the individual’s goals and epistemic values—and they are indexing broad tendencies of pragmatic and epistemic self-regulation at a high level of cognitive con-trol. Continuous variation in both cognitive ability and thinking dispositions can determine the probability that a response primed by Type 1 processing will be expressed—but the continuous variation in this probability in no way
ReflectiveMind
(individual differences in rational thinkingdispositions)
AlgorithmicMind
(individual differencesin fluid intelligence)
AutonomousMind
(few continuous individual differences)
Type 2Processing
Type 1Processing
Fig. 1. The locus of continuous individual differences in Stanovich’s tripartite model of the mind.
by Richard West on May 9, 2013pps.sagepub.comDownloaded from Stanovich KE. (2011). Rationality and the reflective mind. Oxford University Press.
Reflection during case-based learning
Forexample–
• Listthefindingsthatsupportthediagnosis• Listthefindingsthatgoagainstthediagnosis• Listthemissingfindingsyouwouldexpecttobepresentifthis
isthediagnosis• Listalternativediagnoses…
“What’stheevidenceforthisdiagnosis?Whatelsecouldthisbe?”(Engagingthereflectivemind).
Schmidt HG & Mamede S. (2015). How to improve the teaching of clinical reasoning: a narrative review and a proposal. Medical Education; 49: 961-973.
LearningstrategiesthatfacilitateCRdevelopment
BrownPC,Roediger HL,McDanielMA.(2014).Makeitstick:thescienceofsuccessfullearning.HarvardUniveristy Press.
Practiceiscriticalforlearning,withcorrectivefeedbackasnecessary.
Strategiesthatbuildunderstandingaremoresuccessful.
‘Desirabledifficulties’thatelicitmoreerrorsareoftenbeneficial:o Distributed(spaced)practice>massedpracticeo Mixedpractice>massedpracticeo Retrievalpractice(lowstakesquizzing)>repeatedstudy
There are learning strategies, not learning styles
Therearetwoclinicalreasoningworkshopsinthefirstyear.
Bytheendofthis sessionyoushould:
• Knowwhat‘reasoning’means
• Understandwhatismeantby‘rationality’inmedicine
• Beabletodescribedualprocesstheory
• Knowwhatcognitivebiasesareandtheirroleindiagnosis
Learningobjectives
Further resources