Human Errors

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Human Errors

• HI 6001 Healthcare Interface Design
• Week 11

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Intention

• Intention
• NOUN 1. A course of action that one intends to
  follow. 2. Purpose with respect to marriage
  "honorable intentions." 3. Philosophy A concept
  arising from directing the attention toward an
  object. 4. Medicine The process by which or the
  manner in which a wound heals. 5. Archaic Import
  meaning. (American Heritage Dictionary)

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Intentional Actions
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Definition of Error (James Reason)

• Error
• Error will be taken as a generic term to
  encompass all those occasions in which a planned
  sequence of mentalor physical activities fails to
  achieve its intended outcome, and when these
  failures cannot be attributed to the intervention
  of some chance agency.

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Definition of Error (James Reason)

• Slips and Lapses
• Slips and lapses are errors which result from
  some failure in the execution and/or storage
  stage of an action sequence, regardless of
  whether or not the plan which guided them was
  adequate to achieve its objective.

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Definition of Error (James Reason)

• Mistakes
• Mistakes may be defined as deficiencies or
  failures in the judgmental and/or inferential
  processes involved in the selection of an
  objective or in the specification of the means to
  achieve it, irrespective of whether or not the
  actions directed by this decision-scheme run
  according to plan.

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Types of Errors
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Skill-Based Errors (Slips and Lapses)

• Double-capture slips
• A strong habit intrusion. The unintended
  activation of the strongest action schema beyond
  t he choice point.
• I meant to take off only my shoes, but took my
  socks off as well.
• On starting a letter to a friend, I headed the
  paper with my previous home address instead of my
  new one

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Skill-Based Errors (Slips and Lapses)

• Omissions associated with interruptions
• I picked up my coat to go out when the phone
  rang. I answered it and then went out of the
  front door without my coat.
• I walked to my bookcase to find the dictionary.
  In the process of taking it off the shelf, other
  books fell onto the floor. I put them back and
  returned to my desk without the dictionary.

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Skill-Based Errors (Slips and Lapses)

• Reduced intentionality
• I intended to close the window as it was cold. I
  closed the cupboard door instead.
• I went into my bedroom intending to fetch a
  book. I took off my rings, looked in the mirror
  and came out againwithout the book.

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Skill-Based Errors (Slips and Lapses)

• Perceptual confusions
• I intended to pick up the milk bottle, but
  actually reached out for the squash bottle.
• I put a piece of dried toast on the cats dish
  instead of in the bin.
• I began to pour tea into the sugar bowl.

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Skill-Based Errors (Slips and Lapses)

• Interference errors
• I had just finished taliing on the phone when my
  secretary ushered in some visitors. I got up from
  behind the desk and walked to greet them with my
  hand outstretched saying Smith speaking.
• I was just beginning to make tea, when I heard
  the cat clamoring at the kitchen door to be fed.
  I opened a tin of cat food and started to spoon
  the contents into the teapot instead of his
  bowl.

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Skill-Based Errors (Slips and Lapses)

• Overattention mistimed checkes
• I intended to take off my shoes and put on my
  slippers. I took my shoes off and then noticed
  that a coat had fallen off a hanger. I hung the
  coat up and then instead of putting on my
  slippers, I put my shoes back on again.
• I got the correct fare out of my purse to give
  to the bus conductor. A few moments later I put
  the coins back into the purse before the
  conductor had come to collect them.

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Rule-Based Errors I (misapplication of good
rules)

• The first exceptions
• He was about to pull out into the traffic flow
  after having been parked at the side of the road.
  He checked his wing mirror and saw a small red
  car approaching. He then made a cursory check on
  this rear-view mirror and noted a small red car
  still some distance away. He then pulled out from
  the kerb and was nearly hit by a small red car.
  There were two of them, one behind the other. He
  had assumed they were one and the same car. The
  first car had been positioned so that is was only
  visible in the wing mirror.

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Rule-Based Errors I (misapplication of good
rules)

• Signs, countersigns and nonsigns
• Signs inputs that satisfy some or all of the
  conditional aspects of an appropriate rule
• Countersigns inputs that indicate that the more
  general rule is inapplicable.
• Nonsigns inputs which do not relate to any
  existing rule, but which constitute noise within
  the pattern recognition system.

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Rule-Based Errors I (misapplication of good
rules)

• Informational overload
• Rule strength
• General rules are likely to be stronger
• Redundancy
• Rigidity (functional fixedness)
• General versus specific rules

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Rule-Based Errors II (application of bad rules)

• Encoding deficiencies in rules
• Certain properties of the problem space are not
  encoded at all.
• Certain properties of the problem space may be
  encoded inaccurately.
• An erroneous general rule may be protected by the
  existence of domain-specific exception rules.

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Rule-Based Errors II (application of bad rules)

• Action deficiencies in rules
• Wrong rules
• Inelegant or clumsy rules
• Inadvisable rules.

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Knowledge-Based Errors

• Selectivity
• Mistakes will occur if attention is given to the
  wrong features or not given to the right
  features.
• Workspace limitations
• Overload of WM when integrating several mental
  models.

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Knowledge-Based Errors

• Availability heuristic
• Readily available information is more likely to
  be processed first.
• Confirmation bias
• Tendency to confirm a hypothesis, not to
  disapprove it (2-4-6 task).

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Knowledge-Based Errors

• Overconfidence
• Biased reviewing the check-off illusion
• Illusory correlation
• Halo effect
• Problems with causality
• Problems with complexity
• Problems of diagnosis

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Design Principles

• For skill-based performance, experiments are
  necessary to optimize the sensorimotor skills of
  system users.
• For rule-based performance, provide feedback to
  support functional understanding and
  knowledge-based monitoring during rule-based
  performance.

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Design Principles

• For rule-based performance, a display should
  represent cues for actions not only as readily
  interpretable signs, but also indicating the
  preconditions for their validity.
• Simulations for high-risk and potentially
  irreversible systems

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Design Principles

• Information displays of overview information.
• For rule-based performance, reduce possibility of
  falling into procedural traps.
• For knowledge-based performance, reduce the
  chances of interference between possible
  competing mental models by external memory
  support.

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Design Principles

• To aid recovery from errors due to lack of
  resources, use available data to present
  information that is simultaneously suitable for
  skill-based, rule-based and knowledge-based
  processing.
• External memory aids.
• External memory aids.
• External memory aids.