Checklists to Reduce Diagnostic Errors John W. Ely, MD, Mark L. Graber, MD, and Pat Croskerry, MD, PhD
evaluation. The purpose of this article is
often be traced to physicians’ cognitive
to argue for the further investigation and
describes three types of checklists: (1) a
revision of these initial attempts to apply
general checklist that prompts physicians
checklists to the diagnostic process. The
to optimize their cognitive approach, (2)
basic idea behind checklists is to provide
to error, but little is known about how to
a differential diagnosis checklist to help
an alternative to reliance on intuition and
of diagnostic error—failure to consider
the correct diagnosis as a possibility, and
Editor’s Note: A commentary on this article appears
they are well integrated in the workflow,
Cognitive Processes in Diagnosis
suggestions include reflective practice8,9
recognize flaws in the intuitive “thinking”
psychology related to the “dual-process”
1).18 This model proposes two basic modes
and more likely to result in patient harm
than are other types of medical errors.3,4
Given their success in other settings, it is
reflexive, intuitive, and may operate at a
subconscious level. We perform many tasks
might help reduce diagnostic errors.
Checklists are used by airline pilots in all
system-based problems are relatively easy
routinely until the crash of a Boeing 299
they are repeated on a regular basis, these
release the elevator locks.11 Checklists are
subconscious level, and if everything is as it
Dr. Ely is professor, Department of Family Medicine, University of Iowa, Iowa City, Iowa.
used by other high-risk, high-reliability
seems, we perform well. In contrast, Type 2
processes are analytic, slow, and deliberate. Dr. Graber is chief of medicine, Department of
Veterans Affairs Hospital, Northport, New York, andprofessor and associate chair, Department of Internal
Medicine, State University of New York, Stony Brook,
Dr. Croskerry is professor of emergency medicine,
Dalhousie University, Halifax, Nova Scotia, Canada.
intensive care unit staff use checklists to
Correspondence should be addressed to Dr. Ely,
Department of Family Medicine, 01291-D, PFP,
clinical situations that seem familiar, we
University of Iowa Carver College of Medicine, 200
Hawkins Drive, Iowa City, IA 52242; telephone:
(319) 384-7533; fax: (319) 384-7822; e-mail: john-
surgical deaths by half after introducing a
checklists prove effective. For diagnosis,
The purpose of this article is to describe a
generic checklists could force a reflective
First published online January 18, 2011doi: 10.1097/ACM.0b013e31820824cd
potential role for checklists in avoiding
check, and specific checklists could force
Supplemental digital content for this article isavailable at http://links.lww.com/ACADMED/A38.
Academic Medicine, Vol. 86, No. 3 / March 2011
“upstream” problems—those involving
previous encounters—such assuccumbing to the framing bias imparted
RECOGNIZED reflexive) Processes
it is proposed and communicated, to theextent that subsequent physicians may
Calibration† Diagnosis
discount or fail to consider other possible
Processor
“groupthink,” in which the chances oferror increase when the impressions of
RECOGNIZED analytic) Processes Figure 1 A model for diagnostic reasoning based on dual-process theory. Adapted with
permission from Croskerry P. A universal model for diagnostic reasoning. Acad Med. 2009;84:1022–1028. Type 1 thinking can be influenced by multiple factors, many of them subconscious
Perform a focused and purposeful
(emotional polarization toward the patient, recent experience with the diagnosis being
physical exam. The initial hypotheses
considered, specific cognitive or affective biases), and is therefore represented as multiple-
channeled, whereas Type 2 processes are, in a given instance, single-channeled and linear. Type 2override of Type 1 (executive override) occurs when physicians take a time-out to reflect on their
thinking, possibly with the help of checklists. In contrast, Type 1 may irrationally override Type 2
(dysrationalia override) when physicians insist on going their own way (e.g., ignoring evidence-
based clinical decision rules that can usually outperform them).
special attention. However, we must alsolook for signs that might suggest alternate
* “Dysrationalia” denotes the inability to think rationally despite adequate intelligence.68† “Calibration” denotes the degree to which the perceived and actual diagnostic accuracy correspond.
Checklists could help us resist the biases
errors in hospitals, clinics, and emergency
Generate and differentiate initial hypotheses with further history, physical exam, and diagnostic tests.
insultingly obvious (e.g., “Obtain your
improving diagnostic reasoning.2,10 Using
own complete history”), but their routine
problems related to diagnostic testing,26
for most physicians. After all, pilots no
their copilots to release the elevator locks.
• consider a comprehensive differential
The general checklist
posttest period, occurring at rates of 10%
reproducible approach to diagnosis.21 List
1 offers an example of such a checklist.
• develop strategies to avoid predictable
Pause to reflect—take a diagnostic “time-out.” Short of seeking a second
• recognize our altered mood states that
arise from fatigue, sleep deprivation, or
plausibility of the working diagnosis may
be our best tool to avoid error.8,9 The two
context errors and premature closure.5,26
Context errors arise when a critical signalis distorted by the background against
Diagnostic Checklists Obtain your own complete medical
which it is perceived.24 A typical context
Here, we describe three types of checklists
history. There is no substitute for
Academic Medicine, Vol. 86, No. 3 / March 2011
Table 1 Cognitive Biases and Failed Heuristics Addressed by Diagnostic Checklists Bias or heuristic Definition* Role of checklist
The tendency to perceptually lock on to salient features
Prompt physician to consider diagnoses other than the
of the patient’s presentation too early in the diagnostic
process and failing to adjust this impression in light oflater information.
The disposition to judge things as being more likely or
Prompt physician to consider diagnoses other than
frequently occurring, if they readily come to mind.
The tendency to ignore the true prevalence of a
Remind physician of the relative prevalence of diseases
disease, either inflating or reducing its base rate and
in primary care for the patient’s complaint.
The decision-making process ends too soon; the
Prompt physician to reopen the diagnostic process and
diagnosis is accepted before it has been fully verified.
consider alternative diagnoses before discharging the
“When the diagnosis is made, the thinking stops.”
The physician looks for prototypical manifestations of
Prompt physician to consider causes for the symptoms
disease (pattern recognition) and fails to consider
other than the ones that readily fit the pattern.
The tendency to call off a search once something is
Prompt physician to consider additional causes of the
The failure to elicit all relevant information in
Prompt physician to ask questions that might confirm
establishing a differential diagnosis.
The critical signal is distorted by the background
Encourage physician to rethink assumptions and
* Source: Croskerry P. Cognitive and affective dispositions to respond. In: Croskerry P, Cosby K, Schenkel S, Wears
R, eds. Patient Safety in Emergency Medicine. Philadelphia, Pa: Lippincott Williams & Wilkins; 2009:219 –227.
other decisions may take priority, such as
patient’s presentation often changes over
Differential diagnosis checklists
diagnostic errors is our failure to consider
and write “NYD” (not yet diagnosed) in
• Consider the opposite: “Why can’t this
be something else?” Tests that rule out
diagnostic label until our certainty is high
• Use “prospective hindsight”: Derived
Embark on a plan, but acknowledge Proposed General Checklist for Diagnosis uncertainty and ensure a pathway for follow-up.37,38 We often just play the
• Obtain your own complete medical history.
• Perform a focused and purposeful physical
Certainty is not a realistic possibility. The
correct diagnosis often emerges over time
as test results become available or as the
differentiate these with additional history,
patient’s symptoms and signs evolve. This
physical exam, and diagnostic tests.
• Apply decision support tools: A growing
longitudinal aspect of diagnosis mandates
• Pause to reflect—take a diagnostic “time
that we reconsider an initial diagnosis at
diagnosis generators are available, such as
⅙ Was my judgment affected by any other
uncertainties, and lay out a concrete plan
⅙ Do I need to make the diagnosis now, or
ensuring follow-up is a strategy that can
help improve the reliability of diagnosis
uncertainty and ensure a pathway for
Academic Medicine, Vol. 86, No. 3 / March 2011
highlighted in List 2 and detailed in the
dizziness, and so on. The checklists were
revised during two years of use in clinic.
to consider a comprehensive list of causes
of the differential diagnosis checklist is
differential diagnosis checklists, but one
of the authors (J.E.) has noted anecdotal
checklists highlight diagnoses that should
not be missed and those that are, in fact,
checklists in practice. For example, a 90-
anatomy,43,45,46,48 pathophysiology,41,45
after two albuterol nebulizer treatments,
dyspnea. She had been seen four daysearlier with a “COPD exacerbation” and
Example of Differential Diagnosis
to cover 100% of presenting complaints. Checklist Sinus tachycardia
checklists. And within each checklist, our
goal was to cover at least 99% of patients
• Chronic obstructive pulmonary disease
• Pregnancy (10 to 20 beats per minute at
such as constipation and breast lumps.
that did not alter the initial diagnosis and
withdrawal, bupropion, caffeine, cilostazol,
cocaine, ephedrine, epinephrine,isoproterenol, nicotine, tobacco)†
Cognitive forcing checklists for specific diseases
“pneumococcal pneumonia,” “klebsiella
Checklists can serve as cognitive forcing
“right-upper-quadrant pain,” “right-
because we wanted to avoid redundancy.
until the card is removed. Thus, the error
avoided. If the checklist is always built
into diagnostic thinking, then it becomes
generic or specific. In the generic sense,
“ROWS” (rule out worst-case scenario)
• Postural orthostatic tachycardia syndrome
possibilities always receive consideration.
• Chronic nonparoxysmal sinus tachycardia
checklist at the time of admission to help
In the specific sense, checklists may help
determine whether further history taking,
avoid predictable pitfalls for particular
* “Don’t-miss” diagnosis. † Commonly missed diagnosis.
Academic Medicine, Vol. 86, No. 3 / March 2011
address treatment rather than diagnosis. Example of a Disease-Specific Cognitive Forcing Checklist Ankle injury
enough face validity to make such testing
questioned the ethics of allowing patients
to participate in a usual-care arm (i.e., no
safety intervention) in clinical trials of
⅙ Peroneal tendon syndromes (tendinitis,
checklists before adopting them. Instead,
most likely for a particular patient.
⅙ Consider stress films for ankle stability
not been widely adopted in practice,52,53
checklists may have a greater potential for
harm than preflight or surgical checklists.
knowledge base,6 they can be difficult to
For example, they could lead to excessive
incorporate into the workflow,6,54–56 and
consultation or needless testing (although
most serious errors result from doing too
Other interventions similar to checklists
⅙ Missed neurovascular injury (suspect if
⅙ Missed associated fracture (especially
(mental checklists).62 These interventions
learned not to rely on their memories. In
contrast, physicians value superior recall
⅙ Missed Maisonneuve fracture (proximal
organizational structures that differ from
⅙ Missed Achilles tendon rupture (partial or
than mental crutches, reflective thought,
Limitations of checklists
⅙ Missed complex regional pain syndromes
Recent success in adapting preflight-style
stories, but they don’t make great health
checklists for diagnosis may be a “bridge
too far.” The analogy between actionable
forcing strategies will inevitably focus on
intensive care units, or even airplanes.
procedures in diagnosis is not tight. Thoughts are less tangible than actions,
Checklists could produce a false sense ofreassurance that leads to complacency,
Further Considerations and Cautions
whether they have been completed. Inboth medical and nonmedical settings,
checklists are read aloud by teams rather
checklists as a concept that might reduce
aspects of care unrelated to diagnosis.
diagnosis is usually silent, lonely work,
Similar concerns were raised with clinical
and a natural pause point11 to review the
algorithms. It was feared that physicians
kinds of checklists, which we have used in
checklist, such as before takeoff or before
data to support these concerns whenalgorithms were studied in practice.65,66
Related studies
Diagnostic support tools include practice
checklists in this article were not derived
affective state. But rather than unfocused
Academic Medicine, Vol. 86, No. 3 / March 2011
“thunderclap” headache, “worst-ever”
12 Karl R. Briefings, checklists, geese, and 13 Reason J. Human Error. Cambridge,
England: Cambridge University Press; 1990.
an active diagnostic time-out, I reviewed
failure to consider the correct diagnosis
14 Pronovost P, Needham D, Berenholtz S, et al.
An intervention to decrease catheter-related
bloodstream infections in the ICU. N Engl
15 Gawande A. The checklist. The New Yorker. 16 Berenholtz SM, Pronovost PJ, Lipsett PA, et
al. Eliminating catheter-related bloodstream
infections in the intensive care unit. Crit Care
17 Haynes AB, Weiser TG, Berry WR, et al. A Acknowledgments: The authors are indebted to
surgical safety checklist to reduce morbidityand mortality in a global population. N Engl
Conclusions
Amy Miranda, Grace Garey, Mary-Lou Glazer,and Wendy Isser for their expert administrative
18 Sloman S. The empirical case for two systems
of reasoning. Psychol Bull. 1996;119:3–22. 19 Croskerry P. Clinical cognition and
process model of reasoning. Adv Health Sci
Educ Theory Pract. 2009;14(suppl 1):27–35. Ethical approval: Not applicable.
for checklists? (3) Who should review the
20 Croskerry P. Cognitive and affective
dispositions to respond. In: Croskerry P,Cosby K, Schenkel S, Wears R, eds. Patient
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Gabapentin Important drug interactions Clinical use Anti-epileptic – adjunctive treatment of partial• Antidepressants: antagonism of anticonvulsiveseizures with or without secondary generalisation Administration Dose in normal renal function 300 mg on day 1, 300 mg twice daily on day 2,300 mg three times daily on day 3, then increasedaccording to response to 1.2 g daily (in t