3.3 The 5×5 Likelihood × Consequence Matrix
Key Takeaways
- Risk rating = Likelihood (1–5) × Consequence (1–5), giving a score from 1 to 25.
- Likelihood runs from 1 very unlikely to 5 very likely; consequence from 1 insignificant to 5 catastrophic (e.g. death).
- Common Managing Safely action bands: 1–2 maintain controls; 3–6 monitor/improve at next review; 8–12 action within a timescale; 15–16 urgent action; 20–25 stop the activity.
- Worked examples: L3×C4=12 (action band), L5×C5=25 (stop), L1×C2=2 (maintain).
- Matrix scores prioritise action; they are informed judgements, not laboratory measurements — be realistic and consistent.
3.3 The 5×5 Likelihood × Consequence Matrix
Quick Answer: On the Managing Safely 5×5 matrix, score Likelihood (1–5) and Consequence (1–5), then calculate Risk = L × C (range 1–25). Use the score to prioritise action: low scores maintain and monitor; mid scores plan improvements; high scores need urgent control; 20–25 means stop the activity until risk is reduced.
The matrix turns the abstract idea "risk = likelihood × consequence" into a simple tool managers can apply consistently. It is heavily tested on the written paper (calculation and interpretation items) and is mandatory thinking for the workplace risk assessment project, where you rate risks before and after additional controls.
What the matrix is for
The 5×5 matrix helps you:
- Compare different hazards on a common scale
- Decide which issues to tackle first (highest ratings)
- Communicate priority to teams and senior managers
- Show whether extra controls reduced risk (residual rating)
- Link ratings to time-bound actions
It does not replace professional judgement, legal standards, or specialist assessment for complex hazards. Markers know scores are subjective; they look for realistic, consistent ratings tied to clear scenarios — not fantasy zeros or inflated drama.
Likelihood scale (1–5)
Likelihood answers: how probable is the hazardous event, given current conditions and existing controls?
| Score | Descriptor (Managing Safely style) | Plain-language cue |
|---|---|---|
| 1 | Very unlikely | Only in exceptional circumstances |
| 2 | Unlikely | Could happen but not expected in normal operation |
| 3 | Fairly likely | Foreseeable; may occur from time to time |
| 4 | Likely | Probably will occur if nothing changes |
| 5 | Very likely | Expected; almost certain under current conditions |
Some training materials use time-based prompts (for example yearly vs weekly vs daily). Use them as aids, not rigid science. Always score the specific task and people, not the hazard in the abstract. A circular saw in a locked training bay with a competent tutor is not the same likelihood as an unguarded saw used by new starters without supervision.
Factors that push likelihood up:
- High frequency of the task
- Many people exposed
- Poor maintenance, damaged equipment
- Inadequate training or supervision
- History of near misses
- Workarounds and production pressure
Factors that push likelihood down:
- Reliable engineering controls (guards, interlocks, LEV)
- Low exposure time and few people exposed
- Strong procedures that are actually followed
- Competent, experienced people
- Effective supervision and monitoring
Consequence scale (1–5)
Consequence (also called severity) answers: if the hazardous event happens, how bad is the harm likely to be?
| Score | Descriptor | Typical harm band (course style) |
|---|---|---|
| 1 | Insignificant | No injury, or negligible effect |
| 2 | Minor | Minor injuries needing first aid |
| 3 | Moderate | Injury/ill health causing short absence (often taught as up to about three days) |
| 4 | Major | Significant injury/ill health (often taught as more than seven days' absence or serious harm) |
| 5 | Catastrophic | Death, or permanently disabling injury/illness |
Score the realistic worst credible outcome for the scenario, not an impossible movie disaster and not a trivial best case. A fall from a roof is not "minor" because someone might only bruise; a paper cut is not "catastrophic" because infection is theoretically possible.
Consequence may stay high even after good controls if the energy involved is inherently severe (for example working near live high-voltage equipment). In those cases controls mainly reduce likelihood, and residual risk may still demand strict systems of work or stopping the task.
Calculating the risk rating
Risk rating R = Likelihood × Consequence
Possible scores run from 1×1 = 1 to 5×5 = 25. Not every integer between 1 and 25 can occur (for example 7, 11, 13, 14, 17–19, 21–24 are not products of two integers from 1 to 5), which is normal.
Worked examples (memorise the arithmetic)
| Scenario sketch | L | C | R = L×C | Priority signal |
|---|---|---|---|---|
| Rare admin trip on a clear floor with good lighting | 1 | 2 | 2 | Maintain / no extra action beyond keeping controls |
| Occasional manual handling of moderate loads with training | 3 | 3 | 9 | Action / improve within a planned timescale |
| Fairly likely contact with hot surface causing serious burn | 3 | 4 | 12 | Action band — improve controls promptly |
| Likely fall from damaged stepladder with major injury | 4 | 4 | 16 | Urgent action — improve now; stop use of the ladder |
| Likely activity with catastrophic outcome | 4 | 5 | 20 | Stop until risk is reduced |
| Very likely + catastrophic | 5 | 5 | 25 | Stop immediately; fundamental rethink |
Practice items often give descriptors ("likely" and "catastrophic") and ask for the product. Convert descriptors to numbers first, then multiply.
Action bands (commonly taught Managing Safely table)
Use this action-level table, widely taught with the Managing Safely project (LCR rating calculator style):
| Risk rating | Action level | What the manager should do |
|---|---|---|
| 20–25 | Stop | Stop the activity. Take immediate action before restart. |
| 15–16 | Urgent action | Act immediately; stop the activity if necessary; maintain existing controls rigorously while improving. |
| 8–12 | Action | Improve controls within a specified, realistic timescale; assign an owner. |
| 3–6 | Monitor | Look to improve at the next review or if significant change occurs; keep watching effectiveness. |
| 1–2 | No further action / maintain | No extra controls required now, but maintain existing controls and review them. |
Notes for exam and project:
- Highest ratings first. If you have a 20 and a 6, resource the 20 before polishing the 6.
- Timescales must be specific on project forms ("within 2 weeks"), not vague ("soon" / "ongoing").
- After extra controls, re-rate to show residual risk (next section). Residual should be lower if your controls are meaningful.
- Scores such as 9 or 10 fall in the action band (8–12); scores of 15–16 are urgent; 20–25 are stop.
Full grid (mental map)
Think of consequence across the top and likelihood down the side. Darker priority sits toward the bottom-right (high L and high C):
| L \ C | 1 Insig. | 2 Minor | 3 Moderate | 4 Major | 5 Catastrophic |
|---|---|---|---|---|---|
| 1 Very unlikely | 1 | 2 | 3 | 4 | 5 |
| 2 Unlikely | 2 | 4 | 6 | 8 | 10 |
| 3 Fairly likely | 3 | 6 | 9 | 12 | 15 |
| 4 Likely | 4 | 8 | 12 | 16 | 20 |
| 5 Very likely | 5 | 10 | 15 | 20 | 25 |
Using the matrix without fooling yourself
Common rating errors:
- Scoring the hazard name instead of a specific hazardous-event scenario
- Ignoring existing controls (overstating likelihood)
- Assuming controls that are written but not used (understating likelihood)
- Always picking middle scores (3×3) to avoid decisions
- Deflating scores so that nothing needs budget
- Inflating scores for political effect
Good practice:
- Agree rough descriptors in the team so ratings are consistent across shifts
- Cross-check against incident history
- Separate current rating (with existing controls) from residual rating (after proposed extras)
- Write one clear sentence explaining why you chose each L and C
Exam calculation patterns
Expect items such as:
- "Likelihood 4 and consequence 5 — what is the rating?" → 20
- "Which risks are tackled first?" → highest ratings
- "Score of 2 — what action?" → maintain existing controls / monitor
- "4 × 4 damaged stepladder" → 16, urgent improvement; remove from use
Show the multiplication explicitly in your head: convert words → numbers → product → band → action.
Link to the practical project
On the project you typically:
- Describe the hazard and who is at risk
- List existing controls
- Calculate current L × C
- Propose additional controls
- Calculate residual L × C (should fall)
- Assign who monitors and when
- Align timescales with the action band
A current rating of 16 that only drops to 15 after "more PPE posters" will look weak. Aim for controls that realistically cut likelihood (or consequence where possible) enough to move bands.
Manager summary
The 5×5 matrix is a prioritisation engine: define the scenario → score L and C honestly → multiply → act by band → re-score after controls. Master the scales, the product range 1–25, and the stop/urgent/action/monitor/maintain bands, and you will handle both multiple-choice calculations and the numerical heart of the project.
Using the 5×5 risk matrix taught in Managing Safely, how is a risk rating calculated?
A task is assessed as likely (likelihood 4) to cause a catastrophic outcome (consequence 5). What is the risk rating, and what does the top action band require?
On the Managing Safely likelihood scale, what does a rating of 1 represent?
An activity scores 2 on the 5×5 matrix (for example likelihood 1 × consequence 2). What action does the Managing Safely approach suggest?