2.2 Human and Behavioural Factors in Construction Safety
Key Takeaways
Human failures are commonly divided into unintentional errors (slips, lapses and mistakes) and deliberate violations (routine, situational and exceptional), and each type needs a different control.
Human factors are usually analysed under three headings: the job (task and environment), the individual (competence, fatigue, attitude, health) and the organisation (leadership, resources, culture and supervision).
Under OSHA 1994 section 15(2)(c) employers must provide information, instruction, training and supervision, and under CDM 2024 regulation 17 contractors must use only workers who have or are acquiring the necessary skills, knowledge, training and experience.
Disciplining workers without fixing the job and organisational causes of routine violations rarely changes behaviour, because the pressures that produced the shortcut remain in place.
Why human factors are on the syllabus
Most construction accident reports contain an "unsafe act": a harness not clipped on, a guardrail removed, a short cut through an exclusion zone. Stopping the analysis there produces the same accident again. Part 3(D) of the curriculum asks the SSS to look behind the act and ask why a competent adult chose, or failed, to do the safe thing. In Paper 1 this appears in structured questions on accident causation. In Paper 2 it appears in the HIRARC presentation, where controls such as "supervision" or "training" must be specific and believable.
The law points the same way. OSHA 1994 section 15(2)(c) requires employers to provide the information, instruction, training and supervision needed for safety. Section 24 requires employees to take reasonable care and follow instructions. CDM 2024 regulation 17(1)(e) and (f) require contractors to use only workers who have, or are acquiring, the necessary skills, knowledge, training and experience, and to give them suitable supervision, instruction and information.
Types of human failure
The classification below is used widely in OSH management, including in UK HSE guidance (HSG48 Reducing error and influencing behaviour) and NEBOSH construction texts such as the course reference Introduction to Health and Safety in Construction.
| Type | Intentional? | Description | Construction example | Main controls |
|---|---|---|---|---|
| Slip | No | Right plan, wrong action, typically in a familiar task | Operator pulls the wrong hydraulic lever on an excavator | Design: distinct controls, interlocks, guarding |
| Lapse | No | Memory failure: a step is forgotten | Scaffolder forgets to refit a tie after moving it | Checklists, tag systems, independent inspection |
| Rule-based mistake | No | A good rule applied in the wrong situation | Using the usual sling configuration on an unusually shaped load | Lift planning, clear procedures, competent supervision |
| Knowledge-based mistake | No | Wrong decision in an unfamiliar situation | New worker judges a trench safe because it "looks hard" | Training, competent persons, escalation rules |
| Routine violation | Yes | A rule broken so often it becomes the norm | Everyone climbs the scaffold outside the ladder bay | Remove the reason (provide access), supervise, involve workers |
| Situational violation | Yes | Rule broken because the job makes compliance hard | No anchor point exists, so the worker does not clip on | Fix the job: provide equipment, time, space |
| Exceptional violation | Yes | Rare, under unusual pressure or emergency | Entering a manhole to rescue a collapsed colleague | Emergency planning, rescue equipment, drills |
The key exam point: errors are reduced mainly by designing the task and environment to be error-tolerant, while violations are reduced by removing the reasons for them and by leadership and supervision. Training helps both, but training alone cannot fix a situational violation caused by missing equipment.
The three groups of human factors
┌───────────── ORGANISATION ─────────────┐
│ leadership, resources, schedule pressure, │
│ supervision, culture, communication │
└───────────────┬───────────────────────────┘
│ shapes
┌──── JOB ────┐ ▼ ┌──── INDIVIDUAL ────┐
│ task design,│ ──> BEHAVIOUR <── │ competence, health,│
│ equipment, │ │ fatigue, attitude, │
│ environment │ │ risk perception │
└─────────────┘ └────────────────────┘
Job factors
- Task design: awkward reach, poor access, unclear sequence, time pressure built into the programme
- Equipment: missing or unsuitable tools, broken ladders, no anchor points, defective lighting
- Environment: heat, rain, noise that masks warnings, night work, congested work fronts
Individual factors
- Competence: skills, knowledge and experience for the specific task, not just a general trade card
- Physical and mental state: fatigue, heat stress, illness, medication, substance misuse, personal worries (Chapter 10 covers psychological health)
- Attitude and motivation: belief that "accidents happen to other people", overconfidence after years without injury, peer pressure to work fast
- Risk perception: familiar hazards are underestimated, while dramatic but unlikely hazards are overestimated
Organisational factors
- Leadership commitment: whether managers walk the site, fund controls and respond to reports
- Production pressure: piece-rate pay, liquidated damages, concrete trucks queuing at the gate
- Supervision ratio and quality: foremen trained to spot and correct unsafe behaviour
- Communication: language barriers, unclear instructions, information that never leaves the site office
- Learning culture: whether near misses are reported without fear and acted upon
Influencing behaviour on a Malaysian site
- Make the safe way the easy way. Put ladder access where people actually need to go. Pre-install anchor lines. Provide enough PPE in the right sizes. This targets situational violations directly.
- Plan the work, including its pace. Schedule pressure is an organisational cause; raise it with the project manager before it turns into short cuts.
- Supervise visibly and fairly. Correct unsafe acts at the time, explain why, and apply the rules equally to local staff, foreign workers and subcontractors.
- Communicate in the workers' languages. Use mandors or lead hands to translate, use pictures and demonstrations, and check understanding with open questions rather than "faham?" (understood?).
- Use behavioural observation and feedback. Short, structured observations by trained supervisors, followed by a conversation on what was safe and what was at risk, build engagement better than counting violations.
- Recognise good behaviour. Praise and recognition schemes reinforce safe habits, provided they do not reward hiding incidents (for example, prizes for "zero reported accidents").
- Investigate for causes, not culprits. When an unsafe act is found, ask what made it seem sensible at the time. Fix job and organisational causes, and apply discipline only for reckless or repeated deliberate violations.
Safety culture and accident ratios
A safety culture is the shared values, attitudes and behaviours that decide how safety is managed when nobody is watching. Positive cultures show management commitment, worker participation, open reporting, learning from incidents and adequate resources.
Accident-ratio studies are often quoted to show why near-miss reporting matters. The best known is Frank Bird's 1969 analysis, which reported roughly 1 serious injury for every 10 minor injuries, 30 property-damage incidents and 600 near misses. The exact numbers vary between industries, but the lesson is that the same underlying causes produce many minor events before a serious one, and each reported near miss is a free chance to remove a cause.
Scenario: the unclipped harness
During a walkabout the SSS sees two workers on a 7-metre roof edge without their lanyards clipped on.
- Unsafe act (immediate): not clipped on. The SSS stops the work immediately and gets the workers to safety.
- Job factors found: the only anchor is 15 metres away, and the lanyards are too short to reach the work area. This is a situational violation.
- Organisational factors: the roofing subcontractor is behind programme, and nobody planned anchorages in the method statement.
- Individual factors: one worker had only a general induction and no harness training.
The SSS's corrective actions go beyond a warning letter:
- install a temporary horizontal lifeline, or use edge protection instead (a higher control)
- revise the method statement and HIRARC
- arrange harness training for the untrained worker
- record the event as a near miss and brief the lesson at the next toolbox meeting
A scaffolder repositions a tie to fit a hoist but forgets to refit it before handing the scaffold back. How is this human failure best classified?
A routine violation
A knowledge-based mistake
A lapse
An exceptional violation
Workers routinely climb the outside of a scaffold because the only ladder bay is at the far end of a 60-metre run. Which response by the SSS tackles the root of this behaviour most effectively?
Issue warning letters, and deduct wages from anyone caught climbing the scaffold
Repeat the same induction video for all workers, at every toolbox meeting this month
Wait until an injury occurs and then investigate
Provide extra ladder or stair access near the work areas, and supervise its use
Which set correctly lists the three groups of factors commonly used to analyse human factors in workplace safety?
The job, the individual and the organisation
The worker, the client and the DOSH inspector
Hazards, risks and the controls applied to them
Planning, doing and checking
Sections you finish are checked off in the contents.