Human Factors

Indicators of Human Factors
Problems
• Accidents where “human error” is a cause
• Occupational health reports of mental or physical
ill-health
• High absenteeism or sickness rates
• High staff turnover levels
• Low level of compliance with h&s rules
• Behaviour issues identified in risk assessments
• Complaints from staff about working conditions
or job-design

Common Human Failures in
Accidents
• Job Factors:
– Illogical design of equipment & instruments
– Constant disturbances or interruptions
– Missing or unclear instructions
– Poorly maintained equipment
– High workload
– Noisy & unpleasant working conditions

Common Human Failures in
Accidents
• Individual Factors:
– Low skill & competence levels
– Tired staff
– Bored or disheartened staff
– Individual medical problems

Common Human Failures in
Accidents
• Organisation & Management Factors:
– Poor work planning, leading to high work pressure
– Lack of safety systems and barriers
– Inadequate responses to previous incidents
– Management based on one-way communication
– Deficient co-ordination and responsibilities
– Poor management of health & safety
– Poor health & safety culture

Human Failures
• Errors (not intended)
– Slips
– Lapses
– Mistakes
• Violations (deliberate)
– Routine
– Situational
– Exceptional

Human
Failures

Slips
• “Actions-not-as-planned”
• Examples:
– Performing an action too soon in a procedure
– Carrying out an action with too much or too
little strength (e.g. over-torquing a bolt)
– Switching the wrong switch
– Moving switch up rather than down
– Carrying out the wrong check on the right item

Lapses
• Forgetting to carry out an action
• Lose our place in a task
• Can be due to interruptions or distractions
• Example:
– Forgetting to fill switchgear with oil?

Mistakes
• Doing the wrong thing, believing it to be
right
• Consist of:
– Rule-based
– Knowledge-based

Routine Violations
• Breaking the rule has become a normal way
of working within the work group. This can be
due to:
– Desire to cut corners to save time & energy
– Perception that rules are too restrictive
– Belief that rules no longer apply
– Lack of enforcement of the rule
– New workers starting a job where routine
violations are the norm and not realising that
this is not the correct way of working

Situational Violations
• Breaking rule is due to pressures from the
job such as:
– being under time pressure
– insufficient staff for the workload
– right equipment not being available
– extreme weather conditions

Exceptional Violations
• Rarely happen and only then when
something has gone wrong
• To solve a new problem you feel you need
to break a rule even though you are aware
that you will be taking a risk

Influences on behaviour at Work
• Personality
• Attitude
• Motivation
• Experience
• Aptitude
• Intelligence
• Perception

Personality
• The study of what makes each of us a
distinct person
• Some characteristics are shared by all
human beings
• Each person is different in some respects

Attitude
• A person’s point of view, or their way of
looking at something
• Influences the way a person reacts in a
certain situation
• Both good and bad attitudes are
contagious

Attitude Formation
• Attitudes are primarily dependant on:
– Early childhood
– Schooling
– Intelligence
– Experiences
– Progress (or the reverse)
– Economics

Aptitude
• A person’s talent for doing something
• Education should give knowledge and help
to form correct attitudes, while training and
practice are necessary for aptitude

Motivation
• That which makes an individual act as they
do - their reason for doing something
• A drive can be either:
– Appetitive - towards something we want
– Aversive - avoiding something unpleasant
• An event that is followed with reward is
likely to recur (positive reinforcement)
• An event that is followed with punishment
is likely to desist (negative reinforcement)

Experience
• With increasing experience we expect more
competence and an increase in ability to
cope with situations
• However, there is a tendency to cut corners,
as shown in the graph:
Accident
Frequency
Age
Experience
Time

Intelligence
• There needs to be enough mental
stimulation, but not too much
• A person with low intelligence may find
even a routine, mundane job very taxing
• If a person of high intelligence is set a
mundane task, he will probably employ
himself in finding new and less arduous,
but not necessarily safer, ways of
completing a task

Sensory Defects & Screening
• Sensory defects increase with age and
failing health
• We screen out things we are not interested
in or consider not worth listening to
• We can go into “auto-pilot” mode, which
saves effort and allows us to concentrate
on other things, or think ahead. This is
useful, but causes many accidents

Perception of Danger
• Factors involved in perception:
– Signals from sensory receptors
– Expected information from memory
• Signals from sensory receptors and
memory can be misleading, particularly if
we are affected by stress, alcohol, drugs,
fatigue or just familiarity

Perceptual Set
• Also called a “mind set”
• When we have a problem, immediately we
perceive not only the problem, but the
answer
• Further evidence may become available
which sows our original perception to be
faulty, but we are so busy congratulating
ourselves on our intelligent solution that
we fail to see alternative causes &
solutions

Perceptual Distortion
• Perceptions get distorted
• Things which are to our advantage always
tend to be more right than those which are
to our disadvantage

Errors in Perception Caused by
Physical Stressors
• Consider effects of:
– fatigue
– overwork
– overtime
– stress from work and home
• Shift work is a major factor
• Our bodies operate best when we have a
regular routine

Perception and the Assessment
of Risk
• In assessing a risk, there is safety in
numbers
• One persons faulty perception of a risk
could be corrected by another persons
clearer perception
• Perception also depends upon knowledge
& experience - a group will have more to
contribute