Transcript The Field Guide to Human Error Investigations

The Field Guide to Human
Error Investigations
Chapters 7 – 13
“The New View of Human Error”
AST 425
The New View
• Human Error is a symptom of trouble
deeper inside a system
• To explain failure, do not try to explain
where people went wrong
• Instead, investigate how people’s
assessments and actions would have
made sense at the time, given the
circumstances that surrounded them
Chapter 7- New View
• Human error is not the cause, it is the
effect or symptom of deeper trouble
• Human error is not random, it is
systematically connected to features of
people’s tools, tasks and operating
environment
• Human error is not the conclusion of an
investigation, it is the beginning
New View
• Safety is never the only goal in systems that
people operate. Goals are multiple (schedules,
economic, competition, etc.)
• Trade-offs between safety and other goals often
must be made under uncertainty and ambiguity.
People decide to “borrow” from the safety goal to
accomplish these other goals
• Systems are not basically safe, people create
safety by adapting under pressure and acting
under uncertainty
New View- People
• People are vital to “negotiating” safety
under these circumstances
• Under these conditions, human error
should be expected
New View of Error
• Errors/Failures should be treated as:
– A window on a problem which might happen
again
– A red flag in the everyday operation of a
system and an opportunity to learn about the
conditions which caused the failure potential
New View Recommendations
• Seldom focus on individuals- everyone is
potentially vulnerable
• Do not focus on tightening proceduresindividuals need discretion to deal with complex
operations
• Do not get trapped in the promise of new
technology (which will present new opportunities
for error)
• Speak in systemic terms- organizational
conditions, operational conditions, or
technological features
Chapter 8- Human Data, fault
finding
• Traditional investigations have gathered
Human Factors data by:
– Interviewing peers or others who give their
opinion about the people under scrutiny
– Scrutinize training or other relevant records
– Document what people did leading up to the
accident
– Fuels the Bad Apple Theory
Human Data
• The problem of the previous method lies in
human memory:
– Memory is not like a tape which can be
rewound
– Often it is impossible to separate actual
events and cues which were observed from
later inputs
– Human memory tends to order and structure
events more than they actually were- we add
plausibility to fill in gaps
Human Data
• Participants should be allowed to tell their story
with questions from the investigator such as:
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What were you seeing?
What were you focusing on?
What were you expecting to happen?
What pressures were you experiencing?
Were you making any operational trade-offs?
Were you trained to deal with this situation?
Were you reminded of any previous experience?
Chapter 9, Reconstructing the
Unfolding Mindset
• Lay out the sequence of events in time
• Divide the sequence of events into episodes
• Find the data you now know to have been
available to people during the episode- was the
right data available? Was it complete?
• Identify what was observed during the event and
why it made sense (particularly harsh or salient
cues will attract attention even if they are little
understood at the time)- the hard part
Chapter 10- Patterns of Failure
• Technology- new technology doesn’t eliminate
human error, it changes it- attention slips from
managing the process to managing the
automation interface
• Automation relies on monitoring- something
humans aren’t good at for infrequent events
• Many automated systems provide users with
little feedback allowing operators to detect
discrepencies.
Ch. 10
• Pilots often interpret their automation
based on what they believe they have told
it to do and not on the (often weaker more
ambiguous) cues as to what is actually
happening
• It takes a very compelling cue to get pilots
to change this mindset.
Ch. 10- drift
• Accidents don’t just occur, they are the result of
an erosion of margins that went unnoticed- less
defended systems are more vulnerable (ie. A J-3
cub in someone’s barn vs. a 747)
• Often the absence of adverse consequences of
violations lead people down the wrong path- “the
normalization of deviance”- to understand why
we need to understand the complexity behind
the violation
• Recognize that Safety is not a constant- what
causes an accident today may not tommorrow
Ch. 10
• Real progress in safety lies in seeing the
similarities between events which may
highlight particular patterns toward
breakdown (ie. The airbus being in Vertical
speed mode rather than a descent angle
mode)
Chapter 11- Writing
Recommendations
• Can be “high end” (recommending the
reallocation of resources) or “low end”
(changing a procedure)
• The easier a recommendation can be sold,
the less effective it will be- true solutions
are seldom simple and are usually costly
• Recommendations should focus on
change not “diagnosis”
Chapter 12- Learning from Failure
• Use Outside “objective” auditors
• Avoid accepting errors as “just human”
• Avoid “setting an example” of individual
failures- this just makes people avoid
reporting errors
• Avoid Compartmentalization- seek to find
commonalities in failure
• Avoid passing the buck- safety is
everyone’s problem
Ch. 12
• Those making safety decisions should
never divorce themselves totally from the
day-to-day operations becoming immersed
in an idealized world
Chapter 13- In Summary
• You cannot use the outcome of a
sequence of events to assess the quality
of the decisions and actions that led up to
it
• Don’t mix elements from your own reality
now into the reality that surrounded people
at the time. Resituate performance in the
circumstances that brought it fourth
Summary
• Don’t present the people you investigate
with a shopping bag full of epiphanies (“it
should have been so clear!”) as this is
seldom the way the evidence presented
itself
• Recognize that consistencies, certainties
and clarities are products of your
hindsight- not data available to those in
the situation
Summary
• To understand human performance, you
must understand how the situation
unfolded around people at the time- try to
understand how people’s actions made
sense at the time
• Remember the point of a human error
investigation is to understand “why” not to
judge them for what they did not do.
Finally
• Remember the fundamental difference
between “explaining” and “excusing”
human performance- Some people always
need to bear the brunt of a system’s
failure; usually it’s those on the blunt end
of a system (manager’s, supervisors, etc.)