5x5 Risk Matrix Explained: How to Score Likelihood and Consequence

A 5x5 risk matrix gives each hazard on a job hazard analysis two ratings: how likely the hazard is to hurt someone during the step, and how bad the injury would be if it did. Multiply them and you get a score from 1 to 25, which tells the crew how much control the step needs before work starts.

This guide uses the same scoring as the free risk matrix calculator and JHA builder on this site.

How the score works

The score is likelihood times consequence, and each one is rated from 1 to 5.

Likelihood is the chance that the hazard causes an injury during this step, with the crew and conditions you have today.

• 1, Very unlikely
• 2, Unlikely
• 3, Possible
• 4, Likely
• 5, Very likely

Consequence is how bad the injury would be if the hazard does hurt someone.

• 1, Negligible: no first aid needed
• 2, Minor: first aid
• 3, Moderate: medical treatment or restricted duty
• 4, Significant: lost time or hospitalization
• 5, Severe: fatality or permanent disability

The full 5x5 grid

Each cell is the likelihood in that row multiplied by the consequence in that column.

Likelihood	C1 Negligible	C2 Minor	C3 Moderate	C4 Significant	C5 Severe
5 Very likely	5	10	15	20	25
4 Likely	4	8	12	16	20
3 Possible	3	6	9	12	15
2 Unlikely	2	4	6	8	10
1 Very unlikely	1	2	3	4	5

No two whole numbers from 1 to 5 multiply to 17, 18, or 19. That is why the High band ends at 16 and the Extreme band starts at 20.

What each score band means

• 1 to 2, Negligible: proceed with normal supervision.
• 3 to 4, Low: proceed. The crew reviews the controls on the JHA.
• 5 to 9, Moderate: proceed only with the listed controls in place. The supervisor confirms them.
• 10 to 16, High: do not start until added controls bring the score down. The supervisor signs off.
• 20 to 25, Extreme: stop and redesign the task.

These bands are this site’s convention. OSHA’s recommended practices for safety and health programs tell employers to determine the severity and likelihood of incidents for each hazard and use that information to prioritize corrective actions. They do not set a grid size or score cutoffs, so your company or the general contractor may draw the lines in different places. Use the bands your safety program or contract calls for, and use the same bands on every job.

Treat the matrix as a tool for comparing steps and deciding which ones get attention first. Do not read a 12 as twice as dangerous as a 6. A low score also leaves every requirement in a standard in place. If a rule calls for fall protection at 6 feet, the crew provides it even when the step scores Low, and OSHA notes that employers have an ongoing obligation to control all serious recognized hazards.

Scoring before and after controls

The JHA builder scores each step twice. It rates the hazard first with no controls for that step. The after-controls score, often called residual risk, counts the listed controls as in place and working.

Here is an example JHA step for cutting rebar with an abrasive chop saw next to a walkway.

• Before controls, sparks and fragments can hit the operator and anyone walking past. The crew rates likelihood at 4 (Likely) and consequence at 3 (Moderate, a cut or eye injury that needs treatment). The score is 12, which is High.
• After controls, the guard is inspected before use and the operator wears a face shield over safety glasses. The cut station also moves away from the walkway behind a barricade. Likelihood drops to 2. Consequence stays at 3, since an injury that still happens would be about the same. The score is 6, which is Moderate, so the step proceeds with those controls in place and the supervisor confirms them.

Most controls lower likelihood, and a few lower consequence. A personal fall arrest system is meant to stop a fall before the worker hits the level below, which changes the likely outcome of a fall. When a High or Extreme score will not come down with added controls, change the method, for example by assembling the work on the ground and lifting it into place.

OSHA’s hazard prevention guidance lists engineering solutions, including elimination and substitution, first. Safe work practices and administrative controls come next, and personal protective equipment comes last. Look for controls in that order before you settle on an after-controls score.

Keeping scores consistent across crews

Two foremen can look at the same step and pick different numbers. These habits keep scores close from crew to crew.

Anchor examples for consequence

Agree on one or two examples for each consequence level. Here is a starting set:

• 1, Negligible: a scuffed knuckle that needs nothing.
• 2, Minor: a splinter or a small cut cleaned and bandaged from the first aid kit.
• 3, Moderate: a cut that needs stitches at a clinic, or a back strain that puts someone on restricted duty.
• 4, Significant: a hand caught between pipe and a rack that keeps someone off work.
• 5, Severe: a fall through an unprotected floor opening to the level below, or contact with an energized overhead line.

Print your set on the back of the blank JHA, or print the blank 5x5 risk matrix from the templates page and write the anchors beside it.

Anchors for likelihood

Tie the rating to exposure. Ask how often the step is done and how many people are near it while it happens. OSHA’s recommended practices list the number of workers who might be exposed as one factor in evaluating a hazard. Near misses count too. OSHA’s JHA booklet, Publication 3071, treats near misses as a sign that existing controls may not be adequate.

Score as a group

The foreman reads the step, the crew calls out numbers, and the group settles on one. People doing the work notice things that the person holding the clipboard can miss.

Compare scores across jobs

Once a week, the superintendent or safety coordinator can pull JHAs for the same task from different crews and line up the scores. When two crews score the same step far apart, talk it through with both foremen and update the anchor list.

Common mistakes

Scoring the worst imaginable outcome for every step

Anyone can picture a death on almost any task. If every step gets a consequence of 5, every step lands in High or Extreme, and the matrix stops sorting anything. Rate the injury that would realistically happen if this step went wrong today. Keep the 5 for steps where a fatal outcome is realistic, such as work at an unprotected edge or in an unprotected trench.

Lowering likelihood because “we’ve always done it this way”

A crew that has done a task for years without an injury will often rate its likelihood at 1. One crew’s clean record says little about a hazard that causes injuries only rarely. OSHA’s JHA booklet gives priority to jobs with the potential to cause severe or disabling injuries even if there is no history of previous accidents. Score the conditions on site today, including new crew members and work going on overhead.

Scoring after controls that are not in place yet

The after-controls score counts only controls that are installed and checked when the step starts. If the guardrail is on order, the after-controls score for that step is the same as the before-controls score. Either wait for the guardrail or set up an interim control and score that instead. OSHA’s guidance calls for interim controls to protect workers while longer-term solutions are put in place. Fill in the after-controls score at the work area, once the foreman has checked the controls in person.