Night-shift stair fall: two witnesses, one light fitting
At 22:15 a production operative fell on the bottom two steps of a steel stairway connecting the packing hall to the staff corridor, spraining her right ankle. She finished her shift but reported the injury at 07:00 the next morning and was placed on restricted duties for nine days. Two colleagues were within a few metres. One says the stairwell light was out and that he had 'been meaning to report it'; the other says the light was working and that the operative was 'rushing, as usual'. The lamp in question was replaced three weeks later and no failure record exists. A light meter reading taken during your visit at 14:00 gives 40 lux at the stair tread; the site standard for circulation routes is 100 lux. The stairway has a handrail on one side only. The floor was cleaned and polished at 21:00 and the operative was on her fourth consecutive 12-hour night shift, having commuted 50 minutes. She was wearing flat canvas trainers.
1. Assess the reliability of the two witness accounts and design the corroboration you would seek before drawing any conclusion.
Read the worked answer
Assessing reliability - treat both accounts as data to be weighed, not votes to be counted.
Witness A (light out): plausible opportunity to observe (he was nearby), and a self-interested element - 'been meaning to report it' positions him as a concerned observer after the event. That does not make him wrong, but it means his account may be reconstructed to explain what he now knows happened.
Witness B (light working, operative rushing): contains an evaluative judgement ('as usual') that reveals a prior view of the operative; such framing often accompanies blame attribution. He may also have been further away, looking at the light from the corridor side where spill light could make the stairwell appear lit.
Both accounts were given at least a day later, after discussion in the shift, and one has already been paraphrased to a supervisor - memory contamination is likely.
Corroboration to seek
- Re-interview each separately, using free recall first: 'describe what you saw from where you stood', then a sketch of positions and sightlines. Ask what each could actually see of the fitting from where they were.
- Establish objectively whether the light could have been out: maintenance and PPM records, any other fault reports for that stairwell, the fitting's condition and lamp type when replaced, and whether the lighting circuit is on a timer whose settings can be read.
- Ask other night-shift staff whether the stairwell was dark that week - a corridor of independent accounts is better than two.
- Check whether either witness had a role or interest in the lighting checks.
The key point - the fitting has been replaced, so the lamp's state on the night cannot be determined directly. Say that in the report rather than picking the version that fits the preferred conclusion.
2. The 40 lux reading was taken at 14:00, three weeks after the event and after the lamp was replaced. Explain what that measurement does and does not tell you, and what else you would measure.
Read the worked answer
What it does tell you
- Under daylight and with a new lamp, the stair tread still only reaches 40 lux against a 100 lux site standard for circulation routes. That is a design deficiency: the installation is inadequate even when working correctly. This is arguably more significant than the lamp failure, because it would be present every night.
- It shows the site standard is not being verified by any routine measurement, since a compliant-looking stairwell can be at 40% of standard.
What it does not tell you
- It says nothing about conditions at 22:15 on the night: the lamp state then, whether daylight contributed to the 14:00 reading (it almost certainly did), or the age-related output of the old lamp.
- A single point reading is not a survey; the tread edge, the nosing and the bottom step - where she actually fell - may differ from where you held the meter.
- It does not establish causation: 40 lux may be a contributing factor alongside polish, footwear and fatigue, and people descend stairs safely at lower levels routinely.
What else to measure and collect
- A dark-hours survey with a calibrated meter, using a grid of points on each tread and landing, recorded with the time and shutter/door states.
- Floor friction or slip resistance at the stair nosing after the cleaning regime used, and the polish product's drying time versus the 21:00 application.
- The actual cleaning method (was the stair tread polished or only the corridor?), and whether a wet-floor regime or barrier was used.
- Handrail continuity, tread dimensions and nosing condition against the design.
- Roster and commute data for fatigue assessment, and the footwear's sole condition and tread.
Report the lux figure with its date, time and method attached - an unattributed number invites it to be quoted as if it described the night of the incident.
3. The site wants the case recorded as 'no lost time - operative careless'. Explain how you would classify and record the event, and how you would handle the conflicting statements in the report.
Read the worked answer
Classification Use your organisation's written definition rather than the manager's instinct. The facts are: an injury requiring treatment, restricted duties for nine days, and absence from normal work for that period. Under most schemes that is a lost-time or restricted-duty injury, not 'no lost time' - she was not doing her normal work. Check the specific criteria in your jurisdiction and record against them, quoting the definition in the report so the decision is auditable. Separately check whether the case meets any external reporting threshold; do not decide that informally.
'Careless' is a conclusion, not a classification, and it is not a cause. Remove it from the register entry and replace it with what was observed: 'fell on bottom two steps, 22:15, sprained ankle'. Coding an event as carelessness ends the investigation before it starts - which is precisely why 14 similar entries elsewhere on this site have never been examined.
Handling the conflict in the report
- Present both statements verbatim, attributed and dated, with the witness's position and sightline, and note that neither is corroborated.
- State explicitly what could not be determined (the lamp's state on the night) and why - the fitting was replaced before investigation.
- Keep the investigator's opinion in a separate, labelled section; never blend it into the evidence summary.
- Draw conclusions only where evidence supports them: the 40 lux design shortfall, the single handrail, the polish timing, the 12-hour fourth night and the 50-minute commute are all established facts independent of the witness dispute, and any of them may have contributed.
- Recommend a lighting survey, a review of the cleaning regime and drying time, a second handrail, and a fatigue review of the night roster.
Recording 'careless' would also be unfair to the operative, who reported the injury herself the next morning - behaviour the site should be reinforcing, not penalising.