| | The
Psychology of Error
While the consequences
of medical errors can be devastating, in reality, medical errors are not unique.
Medical errors are simply errors in a medical context. As such, we can turn to
what we know about the nature of human error in general to understand why medical
errors occur, what factors produce them, and how to design to reduce them. Slips,
Lapses & Mistakes Cognitive psychologist distinguish
between "skill-based" performance, "rule-based" performance,
and "knowledge-based" performance. Skills are highly practiced behaviors
that we perform routinely, with little conscious effort. They're literally automatic.
Rule and knowledge-based performance requires more mental involvement or conscious
deliberation. We rely on them when skill-based performance won't work, typically
in exceptional or novel situations. Slips
and lapses are errors in the performance of skill-based behaviors, typically
when our attention is diverted. A common mechanism for a slip is "capture",
in which a more frequently performed behavior "takes-over" a similar,
but less familiar one. For example, a capture error
is made when a nurse misprograms a new infusion pump because the sequence of steps
is similar, but not identical to the pump he is most familiar with. Description
errors are slips that occur when the objects of different actions are close
together or visually similar, as when the wrong control on an EKG is adjusted
because it's close to other controls that look the same. Loss
of activation errors are lapses where the goal is forgotten in the middle
of a sequence of actions (e.g., a radiologists forgetting what he is looking for
after retrieving and displaying a comparison study), or we omit a step in a routine
sequence (e.g., the failure to complete a "double-check" for blood-type
in an organ transfer protocol). Slips and lapses occur
while our attention is diverted and we fail to monitor the actions we're performing.
Mistakes
are errors in rule or knowledge-based performance. They arise when we misinterpret
a situation or misapply a rule (usually, a rule that is frequently used and seems
to fit the situation well enough). Mistakes include errors in perception, judgment,
inference, and interpretation. Mode errors are
common mistakes. A mode error arises when we perform an action appropriate for
one mode, but we are mistakenly in another (e.g., when a nurse assumes the default
analgesic concentration of 1.0 mg applies, but the pump was set to 10 mg by previous
user). Misdiagnoses, misinterpretation of test results, failing to provide indicated
prophylactics, and failing to respond to a device alarm are all examples of mistakes. The
Role of Attention As with slips and lapses, attention
plays a key role in mistakes. Whereas attention's job is to monitor skill-based
performance, our attention is actively engaged in the analytical reasoning and
problems solving of rule and knowledge-based performance. As a result, slips,
lapses, and mistakes are all more common when situational factors divert our attention.
Situational factors include physiological factors like fatigue, sleep loss, alcohol,
drugs & illness and psychological factors such as having to juggle multiple
activities, stress, boredom, frustration, fear, anxiety, and anger.
Two
Sides of the Same Coin Errors are a predictable consequence
of basic and normally useful cognitive mechanisms, not random or arbitrary processes.
As error expert James Reason suggests, correct performance and systematic errors
are two sides of the same coin. Top^ | |
