Expanding Perspectives on Misdiagnosis
A significant insight to emerge from the review of the
diagnostic failure literature by Drs. Berner and Graber1is
that the gaps in our knowledge far exceed the soundly
established areas, particularly if we focus on empirical find-
ings based on real-world work by real physicians. This lack
of knowledge about the nature of diagnostic problems
seems odd, given the current climate of concern and con-
centrated effort to address safety issues in healthcare, and
especially given the centrality of diagnosis in the minds of
practitioners. How is it that our knowledge about diagno-
sis—historically the most central aspect of clinical practice
and one that directs the trajectory of tests, procedures,
treatment choices, medications, and interventions—has
been so impoverished?
GAPS IN RESEARCH AND ANALYSIS
The knowledge gap does not appear to be due to lack of
interest in how physicians arrive at a diagnosis. There has
been considerable research aimed at identifying and de-
scribing the diagnostic process and the nature of diag-
nostic reasoning. However, the lack of progress in ap-
plying research findings to the messy world of clinical
practice suggests that we might benefit from examination
of an expanded set of questions. There are at least 5 areas
in which a change of direction might lead to sustained
A great deal of the work to date has assumed that diag-
nostic thinking is best described by highly rationalized
analytic models of reasoning (e.g., the hypothetico-de-
ductive or the Bayesian probabilistic models2,3), with
little or no consideration of alternative approaches. There
are some exceptions, including criticisms of this view
(see Berg and colleagues4,5and Toulmin6), Norman’s
research on clinical reasoning,7,8and Patel and col-
leagues’9studies of medical decision making. Neverthe-
less, the prevailing view in healthcare continues to be that
analytic models of reasoning describe optimal diagnostic
process, i.e., that they are normative. If physicians are not
employing these analytic processes, the assertion is that
they ought to be.
Surprisingly, research in a number of complex fields has
demonstrated that under conditions of uncertainty, time
pressure, shifting and conflicting goals, high risk, and re-
sponsibility for dealing with multiple other actors in the
situation, experts seldom engage in highly analytic modes
of decision making. Rather, under these conditions, experts
are most likely to use fast and generally sufficient strategies.
These strategies (and the methods employed to study them)
have been described within a research paradigm referred to
as “naturalistic decision making.”10–13These findings indi-
cate that we need to better understand the full range of
decision making and diagnostic strategies employed by phy-
sicians and the contexts of their use.
Static Versus Dynamic Decision Problems
Most of the research performed regarding diagnosis in
medical contexts has concerned static decision problems:
only 1 decision needs to be made, the situation does not
change, and the alternatives are clear. (A typical example
is deciding whether a radiograph contains a fracture).
However, much of the work of medicine concerns dy-
namic decision problems: (1) a series of interdependent
decisions and/or actions is required to reach the goal; (2)
the situation changes over time, sometimes very rapidly;
(3) goals shift or are redefined. Decisions that the clini-
cian makes change the milieu, resulting in a new chal-
lenge to resolve.14In contrast to static problems, in
dynamic problems there is no theory or process element
even close to being considered normative, either for ap-
proaching the problem or for establishing a particular
sequence of decisions and/or actions as correct.
Problem Detection and Recognition
One of the greatest holes in our current knowledge base
is the failure to address issues of problem detection and
recognition. Diagnostic problems do not present them-
Statement of Author Disclosures: Please see the Author Disclosures
section at the end of this article.
This research was supported through the Paul Mongerson Foundation
within the Raymond James Charitable Endowment Fund.
Requests for reprints should be addressed to Beth Crandall, Klein
Associates Division, Applied Research Associates, 1750 Commerce Center
Boulevard North, Fairborn, Ohio 45324-6362.
E-mail address: firstname.lastname@example.org.
0002-9343/$ -see front matter © 2008 Elsevier Inc. All rights reserved.
The American Journal of Medicine (2008) Vol 121 (5A), S30–S33
selves fully formed like pebbles lying on a beach. The
understanding that an event represents a “problem” must
instead be constructed from circumstances that are puz-
zling, troubling, uncertain, and possibly irrelevant. In
order to discern the problem contained within a particular
set of circumstances, practitioners must make sense of an
uncertain and disorganized set of conditions that initially
makes little sense.15,16Here, much of the work of diag-
nosis consists of preconscious acts of perception10,17–19
and sense making by clinicians who use a variety of
strategies to discern the real-world context.13Given a
stream of passing phenomena, distinguishing between
items that are relevant or irrelevant, and those that must
be accounted for compared with those that can be dis-
counted, creates a preconscious framing that bounds the
problem of diagnosis before it is ever consciously con-
sidered. This is an important task that has been inade-
quately studied. If we are going to understand how prob-
lems are missed or misunderstood, we need to understand
the processes involved in their detection and recognition.
Traditionally, diagnosis has been considered medicine’s
central task, but it might be useful to entertain the pos-
sibility that this emphasis may be misdirected. Having a
solid diagnosis often makes much of clinical work easier.
However, the lack of a firm diagnosis does not relieve the
practitioner of the necessity to take action, and by taking
action, risk that the world will be changed, perhaps in
unintended ways. Thus, one might argue that the central
task of medicine is not diagnosis, but management, es-
pecially management in the face of uncertainty. Stated
another way, the central question of clinical work might
not be, “What is the diagnosis?” but rather, “What should
we do now?”
Individual Versus Distributed Cognition
Most research on diagnostic decision making has concen-
trated almost entirely on what goes on inside physicians’
minds, focusing on internal mental processes, including
various cognitive biases and simplifying heuristics. Al-
though understanding the individual physician’s cognitive
work is clearly necessary, it is not sufficient. Clinicians do
their work while embedded in a complex milieu of people,
artifacts, procedures, and organizations. All these factors
can contribute or detract from diagnostic performance in
complex ways; the possibility that the diagnostic process
may go awry for reasons other than the physician’s reason-
ing abilities needs more attention. Considering physicians
and their environment as joint cognitive systems,20where
cognition and expertise are distributed across multiple peo-
ple, objects, and procedures within a clinical setting,21of-
fers a way to widen the tight focus from “inside the physi-
cian’s head” so that we can begin to examine this larger, and
far more complex, scenario.
COMPLEXITIES SURROUNDING DIAGNOSIS
One reason we know so little about diagnostic problems
may be the complexity of the systems and work processes
that surround diagnosis. We know that differences in
diagnostic performances exist, but we do not understand
diagnostic failure in any deep or detailed way. In the
emergency department, for example, the physician’s di-
agnostic process is carried out within the context of large
numbers of patients, many of whom have multiple prob-
lems; there is little time, resources are constrained, and
conditions are chaotic. Some possibilities worth consid-
● Context: In what situations, and under what conditions,
are diagnostic failures most and least prevalent? We need
to understand the real-world contexts in which medical
● Team influences: The individual physician is surrounded
by other healthcare providers, including other clinicians,
who share responsibility for patient care and outcome.
How does the distributed nature of patient care foster or
prevent diagnostic failure? In the field of aviation, imple-
mentation of crew resource management (CRM) has been
credited with significant improvements in aviation safety.
CRM requires that the pilot in the second seat voice
concern to the captain and take assertive action if those
matters are ignored. Is aviation’s example a useful ana-
logue? In what ways is it applicable?
● System influences: Some hospital systems have been
highly successful in addressing patient safety issues
such as medication errors and nosocomial infections.
Presumably, the prevalence and severity of diagnostic
failure vary considerably among hospital systems. This
leads to the question, What system-level practices fos-
ter diagnostic quality?
● Individual differences: All physicians make mistakes
but they appear to occur more frequently among some
practitioners, even within a given specialty.22,23We know
that with experience, diagnostic performance improves
but that such progress is not invariant. Some physicians
become extraordinarily skilled at evaluation and are rec-
ognized by their peers as the “go to” person for the
toughest diagnostic challenges. Understanding the ele-
ments leading to such expertise would surely be informa-
tive, as would gleaning why experience appears to en-
hance the diagnostic performance of some physicians
more than others.
DESIGNING EFFECTIVE FEEDBACK MECHANISMS
Identifying the sources of diagnostic failure is a critical first
step towards creating feedback systems that provide lever-
age on the problem. Finding ways to provide feedback on
diagnostic performance seems an important venue for im-
provement, however many difficulties exist. Thus, simply
providing feedback is not a “magic bullet” automatically
leading to improvement. Learning specialists have found
that feedback has greatest impact when it is specific, de-
S31 Crandall and Wears Expanding Perspectives on Misdiagnosis
tailed, and timely.24These 3 issues, and a 4th—the differ-
ential values assigned to different types of failure—repre-
sent significant challenges to designing effective feedback
systems for physicians.
Providing overall data about diagnostic error rates in
physicians is unlikely to get us very far. Grouped data
and general findings leave too much room for individual
physicians to distance themselves from the findings.
However, the processes by which individual physicians’
diagnostic performance might be tracked, tagged, and
reported back to them are not immediately apparent or
To be effective, feedback must give physicians informa-
tion that illuminates contingent relationships and causal
sequences. Otherwise, they are left with unhelpful admo-
nitions such as “work harder, don’t make mistakes, main-
tain a high index of suspicion.” Feedback needs to pro-
vide clinicians with sufficient information so that they
can move in an adaptive direction. The simpler the sys-
tem, the more helpful statistical quality control data are
as a basis for self-correction. Highly complex systems
may prove insufficient because they create dense forests
of information that people—even highly educated, expe-
rienced people—have a great deal of difficulty navigat-
ing. More data are not necessarily helpful. In many cases,
people do not need more data; they need help in making
meaning of the data they have.
The timeliness of feedback, especially regarding diagnostic
performance, may be particularly problematic, as the “final
diagnosis” often is not known for some time and, indeed,
sometimes is never known. Furthermore, in some settings,
delayed feedback can disastrously worsen, rather than im-
Finally, simple feedback mechanisms may lead physi-
cians to become systematically inaccurate in undesirable
ways, owing to differences in value ascribed to various
types of failures. For example, feedback to an emergency
physician showing that he/she discharged a patient who
subsequently proved to have an acute myocardial infarc-
tion is likely to have a much different impact on behavior
than feedback showing that a patient admitted for chest
pain proved not to have an acute coronary syndrome. The
former is likely to be viewed as an adverse event with a
significant affective impact while the latter may be per-
ceived as a nonevent.
Diagnostic failures are both manifestly important and
difficult to comprehend in useful ways. We need to pro-
vide a rich fabric of information that allows members of
the medical community to see what works and what does
not, to hone diagnostic skill, and to hold one another
accountable for the quality of diagnoses. To do this, we
need to enlarge our notions of the nature of clinical work
and of human performance in complex, conflicted, and
Beth Crandall, BS
Klein Associates Division
Applied Research Associates,
Fairborn, Ohio, USA
Robert L. Wears, MD, MS
Department of Emergency Medicine
University of Florida Health Science Center
Jacksonville, Florida, USA
The authors report the following conflicts of interest with
the sponsor of this supplement article or products discussed
in this article:
Beth Crandall, BS, has no financial arrangement or
affiliation with a corporate organization or a manufacturer
of a product discussed in this article.
Robert L. Wears, MD, MS, has no financial arrange-
ment or affiliation with a corporate organization or a man-
ufacturer of a product discussed in this article.
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