Human Error, Accidents, And Safety

Front 1

Human factors

Back 1

Designing things people use in order to enhance performance and minimize errors.

Front 2

Human error

Back 2

Inappropriate or undesirable human decision or behavior that reduces, or has the potential for reducing, effectiveness, safety or system performance.
(undesirable effect of an action/decision)

Front 3

Error

Back 3

* an action or lack of action that violates or exceeds some tolerance limits of the system
* defined in terms of system requirements and capabilities
* does not imply anything about the human

Front 4

______ is cited as one of the most common causes of accidents.

Back 4

Human error

Front 5

Errors of omission

Back 5

failure to perform required action

Front 6

errors of commission

Back 6

incorrect action is performed

Front 7

Subclasses of commission (4)

Back 7

* Sequence errors- step performed out of sequence
* Timing errors- actions performed at the wrong time
* Selection errors- incorrect control is manipulated
* Quantitative errors- too much of too little of the appropriate control manipulation is made

Front 8

Discrete-Action Classifications

Back 8

* Errors of commission
* Errors of omission

Front 9

Intentional Classification

Back 9

error can also be classified according to whether or not the action was performed (or omitted) as intended
* slips
* mistakes

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Slips

Back 10

occur through a failure in execution of action

*deviation from the intended action often provides immediate feedback about the error

Front 11

Mistakes

Back 11

arise from errors in planning/decision

* feedback about error delayed, and more difficult to detect
(mistakes are more serious than slips)

Front 12

Why do people make mistakes?

Back 12

* Inadequate workspace and layout
* Poor environmental conditions
* Inadequate human engineering design
* Inadequate training
* Poor supervision
* Stress
* Lack of knowledge or skill

Front 13

Why not just automate to reduce risk?
(machines can only do what they are programed to do)

Back 13

* Flexibility- people can do more things than machines
* Adaptability- people can solve under defined problems or new situations better
* Ingenuity- people can solve under defined problems better
* Thinking- people can go beyond data, can see possibilities or challenges

Front 14

Flexibility

Back 14

people can do more things than machines

Front 15

Adaptability

Back 15

people can solve under defined problems or new situations better

Front 16

Ingenuity

Back 16

people can solve under defined problems better

Front 17

Thinking

Back 17

people can go beyond data, can see possibilities or challenges

Front 18

How to avoid or reduce risk

Back 18

* build higher quality components and systems
* redundancies to back-up system
* compensations mechanisms that mitigate the failures
* escapes to get away from the consequences of error
* estimate the likelihood of potential human/machine failure and design for it
* recommend improvements in human-machine iteration

Front 19

How to deal with human error

Back 19

* Selection- person's capabilities and skills
* Training- can reduce errors, but expensive and not always effective long term
*Design
-Exclusion designs- impossible to commit error
-Prevention designs- difficult to commit error
-Fail-safe designs- reduces consequences

Front 20

What is often the most cost effective approach?

Back 20

Designing to reduce errors

Front 21

HEP

Back 21

Human Error Probability

HEP = (# of errors) / (# of error opportunities)

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THERP

Back 22

Technique for Human Error Rate Prediction

Front 23

What is an accident?

Back 23

* unexpected, unintentional act, chance

* unanticipated event which demands the system and/or the individual or affects the accomplishment of the system mission or the individual's task

Front 24

What did Suchman do?

Back 24

(1961) produced a list of indicators of the accidental nature of an event

1. Low degree of expectedness
2. Low degree of avoidably
3. Low degree of intention

Front 25

Critical-incident technique

Back 25

description of observed unsafe acts or near-miss accidents described in detail

Front 26

Limitations of accident databases

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* countermeasures to reduce future accidents rarely reported
* focus tends to be on reporting accidents in a method suitable for computer analysis
* trends can be identified, but most accidents are the result of complex chain of events not adequately described
* untrained individuals collecting data
* focus in the injury, not on the case
* not all accidents are reported

Front 27

Accident liability ______ when job demands exceed worker capabilities.

Back 27

increases

Front 28

Adjustment to stress theory

Back 28

accidents will be higher in situations where the level of stress exceeds the capacity of the people to meet it

Front 29

Arousal-alertness theory

Back 29

accidents are more likely to occur both when arousal is too low or too high

Front 30

Describe Swiss cheese model

Back 30

Slices of cheese represent defenses, barriers, and safeguards.
Holes represent failures and latent conditions.
If these holes line up a accident can occur.

Front 31

Errors (HFACS)

Back 31

represent the mental or physical activities of individuals that fail to achieve their intended outcome

Front 32

Violations (HFACS)

Back 32

refer to the willful disregard for the rules and regulations

Front 33

How to reduce accidents by altering behavior
(management type of improvements)

Back 33

* Procedural checklists- list of steps to be executed, memory aid
* Training- help people acquire safe behaviors practices, transferability
* Feedback- reinforces training, maintains change after "intervention"
* Contingency reinforcement strategies- repetition of specific behaviors by providing rewards (reinforcement) when observed
* Incentive programs- incentives for achieving certain safety records

Front 34

Resilience

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intrinsic ability of an organization of system to maintain or regain a stable state, which allows it to continue safe operations after a serious event and/or in the presence of continuous stress

Front 35

Resilience Engineering

Back 35

enables organizations to create processes that are robust yet flexible, to monitor and revise risk models, and to use resources proactively in the face of disruptions or ongoing production and economic pressures

Front 36

Qualities of a resilient system

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* Anticipation- knowing what to expect
* Focus- knowing what to look for
* Feedback- knowing what to respond to
* Response- knowing what to do

Front 37

Risk-important steps

Back 37

procedure steps or actions that expose products, services, or assets to the potential for harm

Front 38

Critical step

Back 38

any action that, if performed improperly, will trigger immediate, irreversible harm