What this is
What is shift fatigue screening?
What is shift fatigue screening?
Assessment of a shift pattern and the work performed on it to identify where fatigue risk is concentrated, using shift design factors, task demands, observed indicators and existing controls, and where warranted a biomathematical model.
What is a biomathematical fatigue model?
A computational model estimating fatigue from work and sleep schedules, based on sleep history and circadian effects. Examples include the HSE Fatigue Risk Index and SAFTE. They take different inputs and produce different scales, so results from different models are not directly comparable.
Scope
When is a shift fatigue screening required?
This screens a shift pattern and the work on it. Individual fitness for duty is separate.
Use this template when
- Assessing a shift pattern before implementation or after a change
- Identifying which shifts and which points within them carry concentrated fatigue risk
- Reviewing patterns following incidents, errors or near misses clustered by time
- Screening overtime, callout and extended-hours arrangements
- Establishing where controls are needed and what kind
Do not use it for
- Individual fitness for duty assessment, which addresses a person on a day
- Working time compliance, which is a legal limit rather than a fatigue assessment
- Occupational health referral for sleep disorders or shift intolerance
- The fatigue risk management system itself, which this feeds
- Journey risk and driving hours assessments, which have their own regimes
Compliance mapping
Which HSE fatigue index requirements does this satisfy?
Fatigue is regulated prescriptively in transport and through general duties elsewhere.
| Clause | Requirement | Where it lands |
|---|---|---|
| ISO 45001 cl.6.1.2 | Hazard identification including work organisation, hours, shift patterns and human factors | Shift design |
| ISO 45003 | Psychosocial risk management including workload, work scheduling and shift work | Task demands |
| HSE Fatigue Risk Index | Screening tool assessing shift schedules for fatigue and risk, based on sleep history and circadian factors | Shift design |
| 49 CFR 395 | Hours of service for commercial drivers, a legal limit distinct from a fatigue assessment | Header |
| Working Time Regulations | Limits on working hours, night work and rest periods (GB and EU) | Header |
| ISO 45001 cl.8.1.2 | Hierarchy of controls, applied to schedule design before reaching alertness measures | Controls |
| ISO 45001 cl.5.4 | Worker consultation on arrangements affecting them, including shift design | Indicators |
| ISO 45001 cl.10.2 | Incident investigation, including whether fatigue contributed | Outcome |
What it does not cover
- Individual fitness for duty assessment, addressing a person on a day.
- Working time compliance, a legal limit rather than a fatigue assessment.
- Occupational health referral for sleep disorders or shift intolerance.
- The fatigue risk management system, which this feeds.
- Driving hours and journey risk assessments, with their own regimes.
How to complete it
How to complete a shift fatigue screening, step by step
Screen the design, ask about sleep rather than hours, and treat the model as one input.
Shift length, start and finish times, direction and speed of rotation, consecutive shifts, rest between shifts, night shift frequency, overtime and callout, and predictability. These are the levers that change fatigue, and most of them can be assessed without any model at all because the physiology is well established.
The model's input is the schedule. The relevant quantity is sleep actually achieved, which is affected by commute, caring responsibilities, second jobs, noise, daylight and shift-related insomnia. A pattern that models acceptably can produce four hours of sleep in practice, and only asking will reveal it.
Fatigue affects tasks unequally. Monotonous monitoring, complex decision-making and driving degrade fastest, while physically active varied work degrades more slowly. Scheduling the most fatigue-sensitive tasks away from the circadian low and the end of long shifts is a control that costs nothing but planning.
Change the pattern, change the rotation, change task allocation, before reaching for napping policies, caffeine guidance and alertness monitoring. Schedule design is the engineering control here, and programmes that skip to individual countermeasures have moved the problem onto the person who is already tired.
What auditors find
Most common shift fatigue screening findings
Fatigue findings concentrate on model misuse and on what the schedule actually produces.
| Finding | Clause | What fixes it |
|---|---|---|
| Model output treated as clearance for a pattern. | CASA guidance | Models cannot give a green light; they are one control among several. |
| Scores from different models compared against a common threshold. | HSE FRI | Models take different inputs and produce different scales; they are not interchangeable. |
| Sleep obtained never asked about, only hours rostered. | ISO 45003 | Commute, caring, second jobs and insomnia all sit outside the roster. |
| Fatigue-sensitive tasks scheduled into the circadian low. | ISO 45001 cl.8.1.2 | Task allocation by time of day is a control costing only planning effort. |
| Controls limited to individual countermeasures. | ISO 45001 cl.8.1.2 | Schedule design is the higher-order control; countermeasures come after. |
| Hours compliance treated as evidence of adequate fatigue management. | 49 CFR 395 | A legal limit is not a fatigue assessment; compliant patterns can be dangerous. |
| No fatigue reporting route, so the model has no field data to check against. | ISO 45001 cl.5.4 | A system needs reported fatigue to validate its predictions. |
| Incidents not analysed by time of day and position in shift. | ISO 45001 cl.10.2 | Clustering by hour and shift position is the most direct fatigue evidence available. |
| Commuting after night shifts not addressed. | ISO 45001 cl.6.1.2 | The drive home follows the shift and is frequently the highest-risk period. |
| Pattern changed without consultation with those working it. | ISO 45001 cl.5.4 | They hold the information about sleep achieved on each variant. |
Case in point
Case in point: what the roster could not see
A site modelled a proposed twelve-hour rotating pattern and obtained results within acceptable limits. The pattern was implemented and the modelling was cited as evidence that fatigue had been assessed.
A subsequent survey of the crew found the average sleep obtained before a night shift was substantially below what the model had assumed. Several people commuted over an hour each way, two had caring responsibilities in the afternoon before nights, and daytime sleep in summer was poor for most of the crew.
None of that information was available to the model, because its input is the schedule. The pattern was, on paper, acceptable. What people were actually sleeping was not.
The template
The template, field by field
The form exactly as it installs. Every field, option, score and conditional rule is editable, and the links to other templates come with it.
6 sections
- Reference
- ERG-024
- Archetype
- Assessment
- Record ID
- FAT-2026-000
- Scoring
- Fatigue risk band
- Direction
- High is bad
- Singleton
- No
- Basis
- HSE fatigue index
- Links
- Links Job, Worker
- Tags
- Ergonomics, Fatigue
- Sections
- 6
- Fields
- 49
- Follow up fields
- 3
- Repeating sections
- 0
- Links out
- 3
Header
14 fieldsScreening ID*
Auto sequence. Format SFS-2026-000.
The record's own ID. Other templates point at this value.
Status*
Drives who this goes to next.
- Planned2 pts
- In progress2 pts
- Complete3 pts
- Deferred0 pts
- Open0 pts
- Closed3 pts
- Overdue0 pts
Date and Time*
Completed By*
Site*
Site ID*
Format SITE-000.
Links to FDN-001 Site ID
Area
The area within the site.
Exact Location
Drop a pin for anything hard to find.
Area 2*
The area within the site.
Exact Location 2
Drop a pin for anything hard to find.
Tired People Make Different Mistakes
Fatigue degrades attention and judgement measurably, and the effect is worse on nights. Screening it is a safety control, not a wellbeing gesture.
Shift Pattern*
- Days only3 pts
- Two shift2 pts
- Three shift rotating1 pt
- Permanent nights0 pts
- Twelve hour1 pt
Screening Period*
Workers Covered*
Shift design
6 fieldsConsecutive Nights Worked*
Shift Length Hours*
Rest Between Shifts Hours*
Rotation Direction
Forward rotation, moving days to afternoons to nights, is easier to adapt to than backward.
- Forward3 pts
- Backward0 pts
- Not rotating2 pts
Notice Of Roster Changes*
- Weeks3 pts
- Days1 pt
- Same day0 pts
Overtime Frequency*
- Rare3 pts
- Occasional1 pt
- Routine0 pts
Task demands
6 fieldsMonotonous Work*
- No3 pts
- Some1 pt
- Highly0 pts
Sustained Attention Required*
- No3 pts
- Some1 pt
- Continuous0 pts
Physically Demanding*
- No3 pts
- Moderate1 pt
- High0 pts
Safety Critical Tasks On Shift*
- No3 pts
- Some1 pt
- Many0 pts
Lone Working*
- No3 pts
- Some1 pt
- Routine0 pts
Break Frequency Adequate*
- Yes3 pts
- Marginal1 pt
- No0 pts
Indicators
6 fieldsFatigue Reported By Workers*
- None3 pts
- Some1 pt
- Widespread0 pts
Incidents Late In Shift
Errors Late In Shift*
- No pattern3 pts
- Some1 pt
- Clear pattern0 pts
Absence Rate On This Pattern
Turnover On This Pattern
Commuting Distance A Factor
- No3 pts
- Some1 pt
- Significant0 pts
Controls
6 fieldsRest Facilities Available*
- Yes3 pts
- Limited1 pt
- No0 pts
Lighting Supports Alertness
- Yes3 pts
- Adequate1 pt
- Poor0 pts
Task Variation Within Shift*
- Yes3 pts
- Some1 pt
- None0 pts
Fatigue Training Delivered*
- Yes3 pts
- No0 pts
Reporting Fatigue Is Safe*
If admitting tiredness gets somebody sent home unpaid, nobody will admit it.
- Yes3 pts
- Uncertain1 pt
- No0 pts
Workload Review ID
Links to HLT-024 Review ID
Outcome
11 fieldsFatigue Risk Level*
- Low3 pts
- Medium1 pt
- High0 pts
Shift Pattern Change Recommended*
- No3 pts
- Yes0 pts
Psychosocial Assessment Triggered*
Action Required*
Raise the action record, then enter its reference here.
- No2 pts
- Yes0 pts
Priority
- High0 pts
- Medium1 pt
- Low3 pts
CAPA ID
Format CAPA-2026-00000.
Links to FDN-014 CAPA ID
Action Owner
Ergonomics*
Signature*
Site Manager*
Second Signature*
ERG-024 · record IDs look like FAT-2026-000 · Links Job, Worker
Open in KnowellaRun it with agents
From a document you fill in to a programme that runs itself
The screen assesses a pattern. What fails is a model output treated as clearance and sleep nobody asked about.
Screens shift design factors directly, records sleep obtained alongside hours rostered, and keeps model output as one input among several.
Analyses incidents and errors by hour and position in shift, which is the most direct fatigue evidence an operation holds.
Provides a fatigue reporting route so predictions can be checked against what people actually experience.
Allocates fatigue-sensitive tasks away from the circadian low and the end of long shifts, which is a scheduling control.
This template lives in KnowErgo — ergonomics. Task assessment, video posture analysis, rotation and workstation redesign.
Meet KnowErgo→Glossary
Shift Fatigue Screening definitions and key terms
- Biomathematical model
- A computational estimate of fatigue from work and sleep schedules, based on sleep history and circadian rhythm.
- Sleep history
- Time awake and accumulated sleep debt, one of the two core physiological drivers of fatigue.
- Circadian low
- The period of the internal daily cycle when alertness is lowest, typically in the early hours.
- Sleep opportunity
- Time available for sleep according to the schedule, which is not the same as sleep obtained.
- Fatigue risk management system
- A multi-layered system of controls, reporting and monitoring within which a model provides a supporting role.
- Rotation direction
- Whether shifts advance forwards or backwards through the day, which affects adaptation.
- Sleep inertia
- Impaired performance immediately after waking, relevant to napping arrangements and callouts.
- Fatigue reporting
- A route for people to report being too tired to work safely, without which a system has no field data.
FAQ
Frequently asked questions about shift fatigue screening
Can a fatigue model clear a shift pattern?+
No, and authoritative guidance says so directly. Civil aviation guidance states that biomathematical models cannot provide a green light for operational safety and should be one of several controls, complemented by monitoring and practices ensuring adequate rest. Industry guidance adds that predictions should never be the sole basis for operational fatigue decisions.
Why not?+
Because models predict fatigue for the average person, without accounting for individual differences, task type or work context. They also take the schedule as input rather than sleep actually obtained, so a pattern that models acceptably can still be producing severe fatigue in people whose sleep is constrained by commute, caring responsibilities or shift-related insomnia.
Can we compare scores between models?+
No. Different models take different inputs and produce outputs on different scales, so a threshold set for one tool means nothing applied to another. This matters when an organisation changes tool or compares itself to a published figure, because the numbers look comparable and are not.
What should we assess without a model?+
Shift length, start and finish times, rotation direction and speed, consecutive shifts, rest between shifts, night frequency, overtime, callout and predictability. The physiology behind these is well established, and a comparative study concluded it is not clear current models add more than an expert with a firm grasp of sleep history and time-of-day effects.
What is the strongest control?+
Schedule design, followed by task allocation by time of day. Moving fatigue-sensitive work away from the circadian low and the end of long shifts costs planning effort only. Napping policies, caffeine guidance and alertness monitoring come after, and a programme that starts there has placed the problem on the person who is already tired.
Keep going
Related templates and programmes
Industries this is written for
Programmes this belongs to
Ergonomics and MSD Prevention
Assessed tasks with before and after scores, and a business case that gets equipment approved.
Fatigue and Shift Work
Fatigue treated as a designed risk rather than an individual failing.
Shift Management
Known problems crossing the handover, and nobody placed on a position they are not signed off for.
Used together in Ergonomics and MSD Prevention
Discomfort Report
Lets a worker report aches, pain or discomfort early, before it becomes an injury
Body Part Symptom Survey
Maps where in the body workers are experiencing discomfort, across a team or area
MSD Injury Report
Records a diagnosed musculoskeletal injury, including affected body part and suspected task
Early Intervention Record
Records the actions taken when discomfort is reported, before it becomes an injury
MSD Trend Review
Reviews discomfort reports and MSD injuries across areas and tasks
Task Ergonomic Assessment
Assesses a work task using video, applying the methods you configure such as RULA, REBA or WISHA
More in Screening
Area Ergonomic Screening
A quick first pass across a whole area to find which tasks need a full assessment
Manual Handling Screening
A rapid check of manual handling tasks to band them by risk
New Task Ergonomic Screening
Screens a new or changed task before it goes live
Screening Follow Up Log
Tracks which screened tasks went on to full assessment and which did not
Written and reviewed by
Siddarth Singh
Founder & Chief Executive Officer, Knowella
Certified Safety Professional and industrial and systems engineer with more than a decade inside food supply chain, freight and manufacturing operations. This page was written against the current text of the standards it cites, not against secondary summaries of them.
- Certified Safety Professional (CSP), Board of Certified Safety Professionals
- MBA, University of Chicago Booth School of Business
- MS and BS, The Ohio State University, Industrial and Systems Engineering
- Six Sigma Black Belt
Sources and last review. Reviewed 16 August 2026 against:
- CASA biomathematical fatigue model guidance document, on limitations and use within an FRMS
- IATA, uses and limitations of biomathematical fatigue models
- Fatigue, alertness and risk prediction for shift workers, University of Surrey and Transport for London
- HSE Fatigue Risk Index tool and supporting research (GB)
- ISO 45003:2021, psychological health and safety at work
This page is general guidance, not legal advice. Confirm requirements with your jurisdiction’s regulator.