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Cognitive Biases 43
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Confirmation Bias
Confirmation bias is the tendency to look for, interpret, favour, and
recall information that confirms or supports our prior beliefs and to
discount disconfirming evidence even when the latter is clearly present. Experiments have found repeatedly that people tend to test
hypotheses in a one-sided way by searching for evidence consistent
with their current hypothesis. In one example, participants read a
profile of a woman that described an equal mix of introvert and
extrovert behaviours. Later, they had to recall examples of her introversion and extroversion – one group was told this was to assess the
woman for a job as a librarian, while the other group was told it was
for a job as an estate agent. There was a significant difference between what the groups recalled, with the librarian group recalling
more examples of introverted behaviours and the sales group recalling more examples of extroverted behaviours.
Common Cognitive Biases
There are different types of cognitive biases, as illustrated in
Figure 7.2. Biases often work together – for example, in overconfidence bias (the tendency to believe we know more than we actually do) too much faith is placed in opinion instead of gathered
evidence. This bias can be augmented by the anchoring effect or
by availability bias and finally by commission bias, with disastrous results. Box 7.2 illustrates some common cognitive biases
applicable to healthcare.
Why Do Cognitive Biases Occur?
Cognitive biases are subconscious errors in thinking that lead
people to misinterpret information from the world around them,
affecting the rationality and accuracy of decisions and judgements. We can clearly see anchoring, search satisficing, confirmation bias, and diagnostic momentum in this case history. But we
cannot see why they occurred. In Chapter 6 we discussed how
good decision-making is highly dependent on knowledge, as well
as motivation, metacognitive skills, and context. It is perfectly
plausible that the cognitive biases seen in this case history
occurred due to problems in each of these categories.
First, regarding knowledge, it is widely accepted that successful
clinical reasoning is highly dependent on knowledge. Search satisficing may occur when a clinician thinks they have found the
cause of a patient’s presentation but they lack knowledge to realise
a particular finding may not be diagnostic after all. For example,
the finding of nitrites and leucocytes in the urine of an elderly
woman who has presented with a fall may lead to a diagnosis of
‘fall due to urinary tract infection’. However, asymptomatic bacteriuria (causing nitrites and leucocytes on urinalysis) is a normal
finding in elderly women and does not necessarily indicate a
urinary tract infection.
Second, motivation is the process that initiates, guides, and
maintains goal-oriented behaviours. It involves biological, emotional, social, and cognitive forces. Different types of motivation
are often described as being extrinsic or intrinsic to the individual
and can be stimulated by adverse or enjoyable conditions or
events. Motivation is also linked to our emotions. For example, a
clinician’s motivation to ‘unpack’ all the available information
may be different if seeing a patient at the end of a difficult 4-hour
long ward round compared with the beginning.
Third, metacognitive skills refer to the ability to think about
one’s own thinking. While some learners develop metacognitive
skills on their own, others need explicit instruction while solving
specific problems. For example, a clinician is engaged in metacognition when they realise they are unsure and decide to look up
‘elevated troponin and breathlessness’ which would yield the
potential diagnosis of pulmonary embolism. There are three facets
of metacognition, described in Box 7.3.
Finally, context can have a powerful effect on our decisionmaking. Ambient factors, such as fatigue, sleep deprivation, and
interruptions are examples of things that impair Type 2 processing
(both reflective and algorithmic). Environmental factors such as
time constraints, physical space, and information technology
have been recognised to either support or impair good decisionmaking [8]. Patients and their relatives/carers can make a
difference too – one study showed that when patients exhibited
‘disruptive’ behaviours, doctors were far more likely to get the
diagnosis wrong if the case was relatively complex [9].
Figure 7.2 Different types of cognitive biases.
Social
biases
Decision
making
biases
Memory
biases
Probability/
belief
biases
The Fifth Doctor
We can gain further insights by looking at what the fifth doctor
possessed, or did, that was different. The fifth doctor in this case
felt that something did not seem quite right. Where did this ‘feeling’
come from? Some possibilities are listed here:
Critical thinking (see Chapter 6) – recognising that anaemia
1.
was unlikely to be the cause of the new symptom of breathlessness because the haemoglobin level had not changed.
Problem representation (see Chapter 4) – if anaemia is not the
2.
cause, we are now faced with a case of acute unexplained breath-
lessness in a patient with a normal physical examination, 12-lead
ECG and chest X-ray.
3. Evidence-based history and physical examination (see Chapter
2) – in deciding the clinical probability of disease, novices tend to
focus on the patient’s history and physical examination findings.
Premature Closure
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is the tendency to prematurely close the decision-making process
and accept a diagnosis before it, and other possibilities have been
fully explored.
Psych-Out Error
Psychiatric patients who present with medical problems are
under-assessed, under-examined and under-investigated because
problems are presumed to be due to, or exacerbated by, their
psychiatric condition.
Framing effect
is when how a case is presented, for example in handover, can
generate bias in the listener. This can be mitigated by always
having ‘healthy scepticism’ about other people’s diagnoses.
Gambler’s Fallacy
is the mistaken belief that if something happens more frequently
than normal, then it will happen less frequently in the future (or
vice versa). In situations where what is being observed is random,
this belief is false.
Representativeness
‘If it looks like a duck, walks like a duck, then it is a duck’.
However, this kind of pattern recognition can lead to atypical
presentations of diseases being missed.
Search Satisficing
is when we stop searching because we have found something
that fits or is convenient, instead of systematically looking for the
best alternative which involves more effort.
Sutton’s Slip
takes its name from a Brooklyn bank robber who explained he
robbed banks ‘because that’s where the money is!’ – the strategy
Hindsight Bias
is when knowing the outcome profoundly influences the
perception of past events and decision making, preventing a
realistic appraisal of what actually occurred – a major problem in
learning from diagnostic error.
Multiple Alternatives Bias
is when there are several possibilities, leading to significant
uncertainty. This is made easier by reverting to a smaller, more
familiar subset of options which can result in the exclusion of
other possibilities.
Omission Bias
is the tendency towards inaction, rooted in the principle of ‘first
do no harm.’ Events that occur through natural progression of
Triage-Cueing
of going for the obvious is referred to as Sutton’s Law, the slip
occurs when other possibilities are not considered.
Order Effects
disease are more acceptable than those that may be attributed
directly to the action of the healthcare team.
Triage ensures patients get sent to the right department. However,
this leads to ‘geography is destiny’ – for example, a diabetic
ketoacidosis patient with abdominal pain and vomiting gets sent to
surgery. The wrong location (surgical ward) stops people thinking
about medical causes of abdominal pain and vomiting.
is about the fact that we tend to remember the beginning and the
end of information presented to us, but usually not all of it –
important to remember in handovers.
Unpacking Principle
is when failure to ‘unpack’ all the available information means
things get missed. For example, if a thorough history is not
obtained from either the patient or carers (a common problem in
Geriatric Medicine) diagnostic possibilities may be discounted.
Visceral Bias
refers to the influence of either negative or positive feelings
Overconfidence Bias
is the tendency to believe we know more than we actually do,
placing too much faith in opinion instead of gathered evidence.
Posterior Probability
occurs when our estimate of the likelihood of disease is unduly
towards patients, which can affect our decision-making.
influenced by what has gone on before for a particular patient –
for example, a patient who has been extensively investigated for
headaches presents with a severe headache and serious causes are
discounted.
Anchoring
describes the common human tendency to rely too heavily on the
first piece of information offered (the ‘anchor’) when making
decisions.
Ascertainment Bias
is when we see what we expect to see (‘self-fulfilling prophecy’).
Box 7.2 Common cognitive biases
For example, a frequent self-harmer attends the ED with
drowsiness – everyone assumes he has taken another overdose
and misses a brain injury.
Attribution Error
is the process of inferring the causes of events or behaviours. For
example, if a patient gets better after a certain treatment (y), we
might assume the diagnosis must be x.
Availability bias
is when things are at the forefront of your mind because you have
seen several cases recently or have been studying that condition in
particular. For example, when the author worked in an epilepsy
clinic, all blackouts were possible seizures.
Base Rate Neglect
is the tendency to ignore the prevalence of a disease which then
distorts Bayesian reasoning (see Chapter 3). In some cases,
clinicians do this deliberately in order to rule out an unlikely but
‘worst case scenario’.
Commission Bias
is the tendency towards action rather than inaction, in the
assumption that only good can come from doing something
(rather than ‘watching and waiting’).
Confirmation Bias
is the tendency to look for confirming evidence to support a theory
rather than discount disconfirming evidence, even if the latter is
clearly present. Confirmation bias is common when a patient has
been seen first by another doctor (e.g. GP or ED doctor).
Diagnostic Momentum
Once a diagnostic label has been attached to a patient (by the
patient or other healthcare professionals) it can gather
momentum with each review leading others to exclude other
possibilities in their thinking.
GP=general practitioner ED=emergency department
Adapted from Croskerry P. (2002). Achieving quality in clinical decision making: cognitive strategies and detection of bias. Acad Emerg Med; 9: 1184–1204.
Cognitive Biases 45
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Box 7.3 Three facets of metacognition
Concept Definition Examples
Metacognitive
knowledge
Metacognitive
monitoring
Metacognitive
control
Adapted from Dunlosky J and Metcalfe J. Metacognition. p. 3. Sage
Publications, 2009.
Knowledge about a
kind of cognition
Assessing the current
state of a cognitive
activity
Regulating some
aspect of a cognitive
activity
Knowledge about how to
improve one’s own learning
Judging whether you are ‘on
the right track’ while
attempting to solve a
problem
Assessing how well you
understand what you are
reading
Deciding to use a new tactic
to solve a difficult problem
A more accurate way of estimating clinical probability is to first
ask yourself, ‘Who is my patient?’ – in other words, the prevalence of disease in the group to which the patient belongs – then
add in information from the history and physical examination
findings. By asking, ‘What causes acute unexplained breathlessness in a 75-year-old woman with cancer on chemotherapy?’ the
fifth doctor was able to consider pulmonary embolism. The doctor also knew the likelihood ratios for different physical examination findings in the presence of pulmonary embolism (i.e., that
the normal findings are entirely consistent with this diagnosis).
Interpretation of diagnostic test results (see Chapter 3) –
4.
knowledge that a significantly elevated high-sensitivity troponin T can be the result of a pulmonary embolism, and that a
quarter of patients with pulmonary embolism, including those
with a large clot load, have a normal 12-lead ECG [10].
All the information was available – it is possible that the first
5.
two doctors who saw the patient did not have all the results
available. But they also failed to explore the patient’s history
and therefore missed the acute onset of breathlessness in this
case (see the ‘unpacking principle’ in Box 7.3).
Even though the fifth doctor was also the most senior doctor to
see the patient, we learned in Chapter 6 that this does not necessarily mean the fifth doctor is an expert or necessarily behaves in
an expert manner. But what we can see is a specific set of
knowledge, skills, and behaviours that made rational thinking
(see Chapter 6, Figure 6.2), and therefore the diagnosis, possible.
These specific knowledge, skills, and behaviours can be taught
within the context of practicing with cases [11].
Cognitive Apprenticeship
Because knowledge deficits are more likely in junior doctors compared with senior ones, it is important that senior doctors do not
take the case presentations of their inexperienced colleagues at
face value. There is clear evidence that good clinical skills are vital
in making a diagnosis, but several studies have reported poor
skills among doctors in training for many aspects of the history
and physical examination [12], as well as problems synthesising
all the available information. Therefore, it is likely that the case
presentations of junior doctors will contain errors and their
learning will be greatly enhanced by reviewing all the available
information (including going back to see the patient) together.
Even if this is not possible in every case, it is a fundamental component of clinical supervision. There is evidence that critical
thinking and metacognition can be learned in the context of solving specific problems, and that this leads to improvements in
decision-making [1, 5].
Cognitive Biases and Expert Intuition
In psychology, heuristics and biases are viewed as efficient
mental strategies with which to deal with an uncertain and
ambiguous world. On many occasions they work but occasionally they fail – but they are not intrinsically bad. Expert intuition
plays an important role in expert professional practice. The
most well-known researcher of expert intuition is Gary Klein
(see further resources). He writes that the more experience people have in any particular field, the more they rely on intuition
which is a natural and direct outgrowth of their experience (see
Box 7.4). In this context, he defines intuition as the way we
translate our experience into action – repeated experiences are
unconsciously linked together to form patterns. Once we recognise a pattern, we gain sense of a situation, we know what cues
to look for and how we should respond. How did the medical
consultant know to look for pulmonary embolism in the case
history? It was a combination of recognising risk factors (age,
cancer, and chemotherapy), linking pulmonary embolism with
causes of unexplained breathlessness in past experience, and
recognising the blood results did not fit the diagnosis of breathlessness due to anaemia.
Box 7.4 The neonatal nurse
Klein tells the story of an experienced neonatal nurse working on an
intensive care unit. Towards the end of an uneventful shift the nurse
walked past a colleague’s patient and noticed ‘it didn’t look right’.
The baby was under the care of a junior colleague who had been
monitoring the vital signs all night. The baby had been lethargic, but
then babies sleep most of the time. Its temperature had been a little
low compared to previously but still within the normal range. A heel
prick blood sample had been performed earlier in the shift and the
Band-Aid on the baby’s heel showed it had bled, causing a dark
blot. The experienced nurse looked more closely. The baby seemed
off colour. She looked at the charts and asked her junior colleague
whether the baby seemed more lethargic that shift. When the
colleague said yes, the experienced nurse went to the telephone.
The baby had sepsis. The experienced nurse knew this, and organised
immediate antibiotics and blood cultures, which were later positive. The
signs were obvious to her – but not to her junior colleague, who had
noted the individual signs but not put them together in a pattern
because she had never seen neonatal sepsis before.
Adapted from Klein G. The Power of Intuition. Doubleday, 2004.
pp.13–19.
46 ABC of Clinical Reasoning
Visible performance
deliberate practice
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(tip of the iceberg)
Effort
Study
Practice
Coaching
Feedback
‘Hidden’ years of
Figure 7.3 The apparent effortlessness of expert intuition.
Experts bring extensive knowledge and experience to a situation,
but only in their specific domain of expertise. This is different to
the subconscious, and sometimes erroneous, shortcuts we are all
prone to in our everyday lives. The apparent effortlessness of
expert intuition is in fact a function of years of deliberate practice
(see Figure 7.3), a concept that is discussed further in Chapter 10.
Summary
Cognitive biases are prevalent in everyday life and in clinical
practice. As described in Chapter 6, they are not necessarily the
‘fault’ of Type 1 processing. There is definitely agreement that
cognitive biases exist in medicine, but disagreement as to whether
they are a significant source of diagnostic errors compared with
knowledge deficits. However, while knowledge, formal and experiential, undoubtedly matters, cognitive biases may also occur
when there are problems with motivation, metacognitive skills,
and the context in which the clinician is operating. Individual differences also play a role. There is good evidence that critical
thinking and metacognition can be taught in the context of
solving specific problems. However, research in the area of
cognitive biases, their relationship to diagnostic error and error
reduction, is in its infancy.
References
1. Croskerry P. (2014). Bias: a normal operating characteristic of the diagnosing brain. Diagnosis; 1(1): 23–27.
2. Tversky A and Kahneman D. (1974). Judgment under uncertainty: heuristics and biases. Science; 185: 1124–1131.
3. Morewedge CK, Yoon H, Scopelliti I et al. (2015). Debiasing decisions:
improved decision making with a single training intervention. Policy
Insights from the Behavioral and Brain Sciences; 2(1): 129–140.
Evans J and Stanovich KE. (2013). Dual-process theories of higher cogni-
4.
tion: advancing the debate. Perspectives on Psychological Science; 8(3):
223–241.
5.
Bransford JD, Brown AL and Cocking RR (Eds). How people learn: brain,
mind, experience and school. Washington DC: National Academies Press,
2000.
Norman GR, Monteiro SD, Sherbino J et al. (2017). The causes of errors
6.
in clinical reasoning: cognitive biases, knowledge deficits, and dual process thinking. Academic Medicine; 92(1): 23–30.
7. Dobelli R. The art of thinking clearly: better thinking, better decisions.
Sceptre, 2013. pp 94–96.
8. Croskerry P. (2018). Adaptive expertise in medical decision making.
Medical Teacher; 40(8): 803–808.
9. Schmidt HG, van Gog T and Schuit SCE. (2017). Do patients’ disruptive
behaviours influence the accuracy of a doctor’s diagnosis? A randomised
experiment. BMJ Quality & Safety; 26: 19–23.
Thomson D, Kourounis G, Trenear R et al. (2019). ECG in suspected
10.
pulmonary embolism. Postgraduate Medical Journal; 95: 12–17.
11. Cooper N, Bartlett M, Gay S et al. (2021). Consensus statement on the
content of clinical reasoning curricula in undergraduate medical
education. Medical Teacher; 43(2): 152–159.
12. Holmboe ES. (2004). Faculty and the observation of trainees’ clinical
skills: problems and opportunities. Academic Medicine; 79(1): 16–22.
Further Resource
CHAPTER 8
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Situativity and Human Factors
Nicola Cooper
OVERVIEW
• Clinical reasoning involves the senses and is complex, contextdependent, and distributed
Human factors studies the limitations of human performance and
•
how people interact with each other, the systems in which they
work, and technology
• To err is human – so in order to minimise errors, we need to focus
on improving processes, systems, and technology
• Clear team communication plays a vital role in the prevention of
errors and adverse events
• Human factors training can be implemented at different levels of
an organisation and tailored to individual teams
Introduction
In Chapter 6 we introduced the idea that clinical reasoning is ‘situated’ in the environment, interdependent with various external
factors such as the patient, information technology (IT) systems,
physical space, time constraints, etc. This view of clinical
reasoning is informed by the situativity theories, a family of
related social theories [1]. Accordingly, knowledge is not
something that exists solely inside a person’s organised cognitive
structures, but is entangled in the activity of providing care for the
patient [2]. This extends to the environment in which care takes
place, and the structures, teams, processes, and resources that can
all facilitate or hinder the diagnostic process (see Figure 8.1). This
chapter expands on some of these ideas and also introduces some
key concepts in human factors.
External
environment,
e.g.healthcare
system,targets,
national
Organisation,
e.g.culture,
staffing,
structure,
processes
guidelines
Diagnosticteam
members,e.g.
patient,family,
Physical
environment,
e.g.space,
resources,ease
of
communication
clinicalstaff,labs,
radiology
Technology,e.g.
EPR,online
resources
Figure 8.1 Elements of the environment in which care takes place.
EPR=electronic patient record. Adapted from Graber ML. (2020). Progress
understanding diagnosis and diagnostic errors: thoughts at year 10.
Diagnosis; 7(3): 151–159.
Embodied
cognition
Situativity
theories
Tasks,e.g.
documentation,
communication,
admin
Ecological
psychology
Situativity Theories
Situativity helps us to understand that clinical reasoning involves
the senses; is complex, context-dependent, and ‘distributed’; and can
go wrong not only because of individual reasons, but for social and
environmental reasons as well. The different situativity theories (see
Figure 8.2) offer distinct but complimentary lenses through which
to view clinical reasoning, and some examples are given below.
ABC of Clinical Reasoning, Second Edition. Edited by Nicola Cooper and John Frain.
© 2023 John Wiley & Sons Ltd. Published 2023 by John Wiley & Sons Ltd.
Situated
cognition
Figure 8.2 Situativity theories.
Distributed
cognition
Embodied cognition is the idea that thinking and learning
depends on our perceptual and motor systems (the embodied
mind). This is particularly the case in procedural specialties. For
48 ABC of Clinical Reasoning
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example, by palpating a large baby, seeing facial plethora, and‘turtling’ a clinician identifies shoulder dystocia and takes action [3].
Ecological psychology is the idea that thinking and learning
takes place in complex, rich information-containing environments. Each environment offers unique affordances (i.e., opportunities to make the right diagnosis). The clinician brings unique
effectivities (i.e., knowledge, skills, and ability to act on those
opportunities). The interactions with the environment are shaped
by the clinician’s intentions (i.e., goals) as well as their attentions
(i.e., recognition of the affordances) [4]. For example, in a busy
resuscitation room, a clinician is dealing with several patients,
including a new 50-year-old man with severe diabetic ketoacidosis (DKA). The patient’s type 1 diabetes is usually well controlled.
Generalised abdominal pain is a common finding in DKA at presentation, but the patient’s wife explains how the abdominal pain
was abrupt in onset. Several different staff members come and go
with new information, including the capillary glucose, ketones,
blood gas result, electrocardiogram, patient’s weight etc. and
information about other patients. On examination, there is generalised tenderness of the abdomen but it is soft. The clinician’s
intention is to treat the DKA, but amidst the necessity to deal with
the DKA, multiple interruptions, and perhaps as a result of their
limited experience, they miss the affordance offered by the
patient’s wife which points to possible surgical pathology as a
cause of the DKA.
Situated cognition is the idea that thinking and learning is context-dependent, the result of multiple dynamic interactions between individuals and the environment. Cognition unfolds
through this complex and evolving interplay between clinician,
patient, and the setting of the clinical encounter [5]. For example,
clinical outcomes are influenced by clinician factors such as their
knowledge and motivation but also their well-being and cultural
background. They are influenced by patient factors such as their
illness presentation, medical literacy, language and culture. They
are also influenced by environmental factors such as appointment
length, location, support, and IT systems, and staffing levels [1].
Finally, distributed cognition is the idea that thinking and
learning is distributed in team members and in non-humans (e.g.,
computers). We see this in multi-disciplinary teams and different
sets of medical records, guidelines, and decision-aids. However,
clinical reasoning can be impaired when a clinician is not able to
access the relevant team members or records, for example [6].
When things go wrong, it is important to understand the complex, context-dependent, and distributed nature of clinical
reasoning. Everything we have learned about patient safety in the
last decades emphasises that ‘to err is human’ [7] – so in order to
minimise errors, we need to focus on improving processes, systems, and technology as well as education and training.
Human Factors
Human factors, also known as ergonomics, is an established
scientific discipline used in many safety critical industries. It is
interested in the limitations of human performance and how
people interact with each other, the systems in which they work,
and technology. A critical aspect of human factors is to do with
the design of equipment, workspaces, processes, and systems that
make it easy for people to do the right thing. This includes staffing levels, rotas, and rest periods.
Our understanding of human factors and how it applies to
healthcare has largely derived from the aviation industry as well
as other safety critical industries such as nuclear power and the
military. Research shows that human factors play a significant
role in the majority of accidents. For example, accident analyses,
simulator research, and cockpit voice recordings show that unsafe
flight conditions are frequently related to failures in cognitive and
communication skills rather than a lack of technical knowledge.
Similar contributory causes are found when accidents in the
operating theatre are analysed [8].
In 2013, England’s Department of Health, along with several
other organisations including Health Education England and
NHS Employers, signed a human factors in healthcare concordat,
stating that ‘The principles and practices of human factors focus
on optimising human performance through better understanding
the behaviour of individuals, their interactions with each other
and with their environment. By acknowledging human limitations, human factors offers ways to minimise and mitigate human
frailties, so reducing medical error and its consequences. The
system-wide adoption of these concepts offers a unique opportunity to support cultural change and empower the National Health
Service to put patient safety and clinical excellence at its heart’ [9].
Human factors is completely integrated into all aspects of
aviation education and personnel are schooled thoroughly in
standard methods of communication. This training is continuous, not a one-off, and it includes everyone. Human factors
training covers 1) understanding error, 2) the limitations of
human performance, and 3) effective communication within
teams.
Understanding Error
The modern patient safety movement was born in the 1990s with
the publication of the Harvard Medical Practice Study [10]. The
authors looked at sue-able adverse events in a group of hospitals
and calculated that, if the incidence was the same in all US hospitals, the harm caused was the equivalent of a fatal jumbo jet crash
every day. However, it took several years before healthcare organisations and governments began to accept that significant avoidable harm was a problem. The landmark publication, ‘To err is
human: building a safer health system’ [7] followed by the UK’s
‘An organisation with a memory’ [11] helped to kick-start the
global patient safety movement that exists today.
In 2001, a paper was published in the BMJ which found that
adverse events occurred in 10% of UK hospital admissions,
directly leading to death in 1% [12]. Around half of adverse events
were judged to be preventable. Similar figures have been reproduced in several different countries around the world. Research
commissioned by England’s Department of Health estimated that
preventable adverse events cost the National Health Service up to
£2.5 billion each year, or 2.5% of its budget.
Situativity and Human Factors 49
Hazards
Successive layers of defences, barriers and safeguards
Some holes due to active
failure (eg. mistakes,
procedural violations)
Losses
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While healthcare has become more effective it has also become
more complex, with greater use of new technologies, medicines,
and treatments. The World Health Organization defines patient
safety as ‘the prevention of errors and adverse events to patients
associated with healthcare’. An error is an unintended act (either
of omission or commission) or one that does not achieve its
intended outcome. This could be due to the failure of a planned
action to be completed as intended (an error of execution), the
use of a wrong plan to achieve an aim (an error of planning), or a
deviation from the process of care. Errors may or may not result
Other holes due to latent
conditions (eg. faulty equipment,
lack of staff training or experience)
in harm, and can sometimes be intercepted. An adverse event is
what happens when an error results in harm, and can be mild,
moderate, or severe.
Figure 8.4 Swiss cheese model of accident causation. Reproduced with
permission from Reason, J. Human Error. Cambridge University Press, 1990.
Bird’s triangle, from industry (see Figure 8.3) is a visual representation showing that for every severe adverse event there are
likely to be 600 incidents with no injury or damage. The implication is that by tolerating unsafe acts or near misses that could be
due to poorly designed systems or processes, adverse events are
more likely to occur. This is one reason why there is mandatory
incident reporting in the aviation industry. However, while this is
human system, these defences, barriers, and safeguards can have
‘holes’ in them. If these holes happen to align, a severe adverse
event can occur. The important thing to understand is that in
order to prevent an adverse event from happening again, the
latent conditions (root causes), as well as any active failures, need
to be addressed.
a useful model, it does not take into account that adverse events
often have multiple causes in which an unrelated event can occur
The Limitations of Human Performance
at the same time which turns a minor incident into a major one.
This is illustrated powerfully in the UK Department of Health’s
award-winning video Just an Ordinary Day [13].
Research shows that, in general, errors are predictable and tend
to repeat themselves in patterns. We, the systems in which we
work, and the processes that are in place, can either adapt for this
and make error and adverse events less likely, or can in fact create
‘accidents waiting to happen’. This is particularly pertinent to the
design of equipment, IT systems, and procedures.
Severe adverse events often occur after a series of smaller
things go wrong – this is referred to as an ‘error chain’, illustrated
by Reason’s Swiss cheese model in Figure 8.4. For example, blood
transfusion has a series of defences, barriers, and safeguards, from
The human brain is wired to miss things that are obvious, see patterns that do not exist, and jump to conclusions. Take a look at
Box 8.1 but only for a few moments, enough to read the sentence
twice. Now cover it up and say how many F’s there are.
When this experiment is given to a room full of people, there is
a range of opinion. Some people see two F’s, some see three, some
see four, five, or six. Everyone is trained to read English, and
everyone is looking at the same thing, so what is happening?
Experiments like these are used to teach something called
‘situation awareness’. Individuals can have situation awareness, but
a team’s situation awareness can be low if no one communicates,
especially when something appears to be ‘obvious’ (see Box 8.2).
donation to screening to storage to administration. But in any
Box 8.1 How many F’s are there?
1 severe injury
Take only a few moments to read the following sentence twice:
FINISHED FILES ARE THE RESULTS OF
YEARS OF SCIENTIFIC STUDY
10 minor
injuries
COMBINED WITH THE EXPERIENCE
OF YEARS
Figure 8.3 Bird’s triangle.
Unknown number of unsafe acts
30 damage accidents
600 near misses
Box 8.2 Situation awareness
‘A light aircraft is heading towards an airport surrounded by
mountains. The captain has inadvertently descended below the
minimum safe altitude and the aircraft is on a collision course with
the mountain. It is the co-pilot’s first day and he can see that the
aircraft is headed towards the mountain. The captain is experience
and has flown this route many times before. He is bored and
pre-occupied with problems at home. The co-pilot reasons that such
an experienced captain surely knows what he is doing. Is there any
need to say anything?’
McAllister B. Crew resource management. Airlife Publishing Ltd, 1997.
50 ABC of Clinical Reasoning
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Drew and colleagues asked 23 consultant radiologists to look at
CT scans of the thorax specifically to look for lung nodules.
Unknown to the radiologists, the researchers inserted a matchbox-sized image of a gorilla in some of the scans. They found that
83% of the radiologists missed the gorilla, which was 45 times
larger than the average lung nodule, even though they spent an
average of 5.7 seconds looking at the gorilla-containing images
and their eyes fixed briefly on the exact location of the gorilla
[14]. This experiment highlights that we are only aware of a small
part of our visual world at any one time. We focus our attention to
filter out distractions, but in focusing on what we are trying to see,
we tend not to notice the unexpected.
Our perceptions and performance can be fallible at the best of
times, but are also adversely affected by:
•
Sleep deprivation
•
Fatigue
•
Stress
•
Excessive workload/cognitive overload
•
Illness
One study showed that relatively moderate levels of fatigue among
doctors due to night-shift work impaired performance to an
extent equivalent to or greater than is currently acceptable for
alcohol intoxication [15]. The pathways in the brain involved in
Type 2 processing are most affected by things like sleep deprivation, fatigue, and cognitive overload. Figure 8.5 shows how various factors combine to increase the likelihood of human error.
How can an individual mitigate against the limitations of
human performance? The following tips are taken from a ‘how to
guide’ for implementing human factors in healthcare [16].
•
If you are stressed and having trouble concentrating, consider
yourself at greater risk of making a mistake and act accordingly
(e.g., by taking a break, letting a colleague know, or asking for help).
•
In emergency situations quickly allocate a leader. Rehearse
emergency drills as a team.
•
Perform complex drug calculations away from distractions and
get them checked by someone else.
•
Do not rely on your memory; use checklists and standard
operating procedures to improve compliance with best practice.
•
Be aware that humans often see what they expect to see – this is
known as ‘involuntary automaticity’. Double check at key stages
of procedures with colleagues.
•
If a task requires focus and concentration, ensure you cannot be
distracted.
•
Simplify your environment and clinical processes as far as
possible.
However, it is the also duty of the employer to work with healthcare professionals to ensure that the environment, staffing levels,
rotas, design of equipment and IT, workspaces, and processes
make it easy, rather than difficult, for people to do the right thing.
Effective Communication within Teams
Communication within teams is extremely important when
humans are working in volatile, uncertain, complex, and ambiguous clinical environments. In aviation, a trainee pilot must pass
a language proficiency test, participate in courses that teach standardised communication between team members, and pass theoretical and practical communication examinations. While specific
courses on human factors, or ‘non-technical skills’, forms part of
some specialty postgraduate training (see Box 8.3), training in
team communication is not necessarily a formal part of training
for clinicians, despite the fact that poor communication plays a
role in the majority of severe adverse events in healthcare.
For effective communication to occur, the message needs to be
clear in the first place. Then the message has to get through competing demands to the recipient. Then it has to be heard, interpreted, and translated into action.
Clear communication involves:
•
Stating the obvious
•
Announcing what you are doing
•
Not using pronouns (e.g., he, she, it, they)
Internal factors
•↓ Knowledge
•↓ Training
•↓ Confidence
•↑ Emotions
•↑ Fatigue
•↑ Stress
•↑Illness
ERROR
Figure 8.5 Factors affecting the likelihood of human error.
External factors
• Workload
• Interruptions
• Patient factors
• Team factors
• Insufficient data
Box 8.3 The domains of Anaesthetists’ non-technical skills
training
Team work Task management
Co-ordinating activities with the
team
Exchanging information
Using authority and assertiveness
Assessing capabilities
Supporting others
Situation awareness Decision-making
Gathering information
Recognising and understanding
Anticipating
Adapted from Flin R, Patey R, Glavin R et al. (2010). Anaesthetists’
non-technical skills. British Journal of Anaesthesia; 105(1): 38–44.
Planning and preparing
Prioritising
Providing and maintaining
standards
Identifying and utilising resources
Identifying options
Balancing risks and selecting
options
Re-evaluating
Situativity and Human Factors 51
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•
Using ‘readback’ – repeating back information to ensure it is
correct
•
Clearly stating what you want from someone
•
Clearly articulating safety concerns
•
Listening to others
For example, as a junior doctor, the author was on a respiratory
ward round. The consultant, senior resident, author, and ward
sister were all looking at a chest X-ray. After several minutes, the
doctors declared it was normal – until the ward sister pointed out
the huge pneumothorax on the left side. She almost did not speak
up, thinking the abnormality was so obvious the doctors must
have seen it. But in most of the cases of wrong site surgery in the
UK, there was someone in the operating theatre who knew it was
the wrong side, but did not feel able to speak up. The World
Box 8.5 Red flags
Red flags, or warnings, often occur in
the minutes leading up to an adverse
event. They are a sign you could be in
an error chain. Examples of red flags
include:
• Confusion
• Conflicting or missing information
• Departure from standard procedure
• Unease
• Denial or irritability
• Inaction
• Alarms
• Alarming thoughts
Health Organization’s safe surgery checklist includes a ‘time out’
before each operation during which team members must
positively confirm the identity of the patient and the correct site
(including side) of the procedure. The use of this checklist has led
to a significant reduction in surgical morbidity and mortality and
is now used around the world [ 17 ].
Announcing what you are doing is vital in emergency situations where an entire team is working simultaneously – it would
be very easy to accidentally administer the same drug again, or
not give it at all thinking that someone else has already done it.
Problematic pronouns (he, she, it, they) are rife in clinical practice
and can easily lead to the wrong patient or object being identified.
The use of ‘readback’ for verbal orders (e.g., for medication) and
messages (e.g., telephoned blood results) has also been shown to
significantly reduce errors in communication.
The SBAR (situation, background, assessment, recommendation) system of communication originated in the military and is
illustrated in Box 8.4 . In healthcare, it has been shown to increase
the amount of relevant information being communicated and in a
shorter time. Probably the most useful component of SBAR is the
final part – recommendation – in which the person communicating states what they want to happen next.
Finally, clearly articulating safety concerns and listening to
others is vital, as in the scenario in Box 8.2 . ‘Red flags’ are warnings, often occurring in the minutes leading up to an adverse
event. Examples of red flags are shown in Box 8.5 . A red flag is a
cue for action, it means you have to stop to communicate with the
rest of the team so the situation can be re-assessed. Other people
may simply not see what you can see, no matter how experienced
they are – remember, to err is human.
Embedding Human Factors in Healthcare
How does healthcare adopt human factors – from understanding
error, to design of equipment, workspaces, rotas, systems, and
processes that make it easy for people to do the right thing, to
improved communication within teams?
One way is to introduce human factors training for everyone.
Box 8.4 The SBAR system of communicating
Fire safety training, for example, is mandatory for staff in
S Situation
I am [name/designation] calling from [location]
The reason I am calling is because I have a patient with a NEWS2*
of 9 and he needs to be reviewed by a doctor a.s.a.p.
B Background
Patient [name] was admitted on [date] with pneumonia
He is normally fit and well
His oxygen requirements have been increasing throughout the
course of the day and now he is hypotensive
A Assessment
His vital signs are [read out vital signs]
I think the problem is …
OR I am not sure what the problem is but [name] is deteriorating
I have [actions performed so far]
R Recommendation
I would like you to come and see [name] within the next 15 minutes
The listener can readback a summary of the SBAR. The caller can
readback any instructions to ensure that they have been heard correctly.
*National Early Warning Score (NEWS2).
https://www.rcplondon.ac.uk/projects/outputs/national-early-
warning-score-news-2 (accessed April 2022).
Master’s
degree
Training for clinical
leaders and managers
Specific team training
(e.g., theatres, delivery suite, ED)
Human factors training for all staff
(including healthcare assistants, porters, receptionists)
Figure 8.6 A human factors training ‘hierarchy’. ED=emergency
department. Front-line staff need greater training in error and team
communication, whereas clinical leaders and managers need greater
awareness of systems, processes, and equipment design.
52 ABC of Clinical Reasoning
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healthcare organisations in the UK, yet adverse events in healthcare, in which human factors play a large part, harm far more
people than fire. Figure 8.6 illustrates a human factors training
‘hierarchy’ that could be implemented in a typical healthcare
organisation.
Summary
Situativity helps us to understand that clinical reasoning involves
the senses; is complex, context-dependent, and distributed; and
can go wrong not only because of individual reasons, but for
social and environmental reasons as well.
The scale and nature of error in healthcare means it is important for healthcare organisations to employ the scientific discipline of human factors, used in many other safety critical
industries. A critical aspect of human factors is to do with the
design of equipment, workspaces, processes, and systems that
make it easy for people to do the right thing. Healthcare professionals and teams who are trained in human factors can act in
ways that are safer and communicate with each other in a standardised way that enhances patient safety.
References
1. Durning SJ and Artino AR. (2011). Situativity theory: a perspective on
how participants and the environment can interact: AMEE Guide no 52.
Medical Teacher; 33(3): 188–199.
2. Koufidis C, Manninen K, Nieminen J et al. (2022). Representation, interaction and interpretation. Making sense of the context in clinical
reasoning. Medical Education; 566: 98–109.
3. Daniel M, Wilson E, Torre D et al. (2020). Embodied cognition: knowing
in the head is not enough. Diagnosis; 7(3): 337–338.
4. Daniel M, Torre D, Durning SJ et al. (2020). Ecological psychology: diagnosing and treating patients in complex environments. Diagnosis; 7(3):
339–340.
5. Daniel M, Durning SJ, Wilson E et al. (2020). Situated cognition: clinical
reasoning and error are context dependent. Diagnosis; 7(3): 341–342.
6. Wilson E, Seifert C, Durning SJ et al. (2020). Distributed cognition: interactions between individuals and artifacts. Diagnosis; 7(3): 343–344.
7. Kohn LT, Corrigan JM and Donaldson MS (Eds). To err is human:
building a safer health system. National Academy Press, 2000.
8. Clinical Human Factors Group. Never? Report, 2012. https://chfg.org/
never-report (accessed April 2022).
9. A concordat from the National Quality Board. Human factors in healthcare. London, 2013. https://www.pslhub.org/learn/improving-patientsafety/human-factors-improving-human-performance-in-care-delivery/
human-factors-in-healthcare-a-concordat-from-the-national-qualityboard-2013-r52/ (accessed April 2022).
10. Brennan TA, Leape LL, Laird NM, Herbert L, Localio AR, Lawthers AG
et al. (1991). Incidence of adverse events and negligence in hospitalised
patients. Nejm; 324: 370–376.
11. Department of Health. An organisation with a memory. Report of an
expert group on learning from adverse events in the NHS. DH, 2000.
12. Vincent C, Neale G and Woloshynowych M. (2001). Adverse events in
British hospitals: preliminary retrospective record review. BMJ; 322:
517–519.
13. Department of Health. Just an ordinary day: safe administration of
intrathecal chemotherapy. DH, 2003. https://youtu.be/oNCObzqSMa0
(accessed April 2022).
14. Drew T, Vo MLH and Wolfe JM. (2013). The invisible gorilla strikes
again: sustained inattentional blindness in expert observers.
Psychological Science; 24(9): 1848–1853.
15. Dawson D and Reid K. (1997). Fatigue, alcohol and performance
impairment. Nature; 388: 235.
16. Patient Safety First Campaign. The ‘how to guide’ for implementing
human factors in healthcare. https://chfg.org/category/all-resources/
how-to-guides/ (accessed Sep 2015).
17. World Health Organization. Surgical Safety Checklist. www.who.int/
teams/integrated-health-services/patient-safety/research/safe-surgery/
tool-and-resources (accessed April 2022).
Further Resources
1. Vincent C. Patient safety, 2nd Edition. BMJ Books, 2010.
2. Clinical human factors group. https://chfg.org (includes e-learning mod-
ules) (accessed April 2022).
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