How do you calculate an ergonomic risk score?

Multiply each factor by its weight and sum: severity x 0.40 + occurrence x 0.35 + detection x 0.25. With severity 8, occurrence 6, and detection 7, the score is 7.05.

What is a good ergonomic risk score?

Lower is better. On a 1-10 input scale, scores under about 4 are typically low priority, 4-7 warrant review, and above 7 (like the 7.05 example) flag tasks for near-term redesign.

Why is severity weighted more than detection?

Severity carries the highest weight (0.40) because the consequence of a back injury or chronic strain dwarfs how easily the hazard is spotted. Detection is weighted lowest (0.25) since a controllable hazard still injures if severity and frequency are high.

Is this the same as an FMEA RPN?

It borrows the severity-occurrence-detection structure of FMEA but uses a weighted average rather than a simple product (RPN). The weighting prevents a single mid-range factor from dominating the way multiplication can.

How do I score the detection factor?

Rate how hard the hazard is to catch before it causes harm — a high score means the strain is subtle or builds slowly (poor detection), a low score means it is obvious and easily flagged during routine observation.

Can this replace a REBA or RULA assessment?

No. It triages which jobs to study; REBA, RULA, or the NIOSH lifting equation then quantify the biomechanical exposure on the tasks this score flags as high priority.

Safety & Workforce calculator

Ergonomic Risk Score Calculator

The Ergonomic Risk Score condenses three FMEA-style factors — severity, occurrence, and detection — into one weighted number that ranks musculoskeletal hazards at a workstation. EHS managers and ergonomists use it to triage which jobs to redesign first across a plant where every task carries some lifting, reaching, or repetition risk. It matters because gut-feel prioritization misses the high-severity tasks that are also hard to catch before injury, exactly the ones that drive recordable MSDs and workers' comp cost. By weighting severity heaviest (0.40) and detection lightest (0.25), the score reflects that a serious, frequent, hard-to-spot hazard deserves attention before a minor one.

What this calculator does

Score ergonomic risk from posture, force, and repetition factors.
Use it when ergonomic risk in safety and workforce needs a defensible ranking against other safety and workforce risks for the next review.
It computes a single weighted ergonomic risk score from severity (40%), occurrence (35%), and detection (25%) factors.

Formula used

Weighted score = severity × 0.40 + occurrence × 0.35 + detection × 0.25

Inputs explained

Severity factor: undefined
Occurrence factor: undefined
Detection factor: undefined

How to use the result

Use it to rank ergonomic hazards across workstations when prioritizing which jobs to redesign or assess in depth.
It is a relative prioritization index, not a validated exposure assessment — it does not replace RULA, REBA, NIOSH lifting equation, or the Liberty Mutual tables for quantifying actual biomechanical load.

Current U.S. benchmarks

Manufacturing hourly earnings average $30.27 (BLS, Jun 2026), up 4.4% from a year earlier. Median machinist pay is $28.24/hr (OEWS 2025), with state medians on each state page. Manufacturers have 529k open positions nationally (BLS JOLTS).

Common questions

How do you calculate an ergonomic risk score? Multiply each factor by its weight and sum: severity x 0.40 + occurrence x 0.35 + detection x 0.25. With severity 8, occurrence 6, and detection 7, the score is 7.05.
What is a good ergonomic risk score? Lower is better. On a 1-10 input scale, scores under about 4 are typically low priority, 4-7 warrant review, and above 7 (like the 7.05 example) flag tasks for near-term redesign.
Why is severity weighted more than detection? Severity carries the highest weight (0.40) because the consequence of a back injury or chronic strain dwarfs how easily the hazard is spotted. Detection is weighted lowest (0.25) since a controllable hazard still injures if severity and frequency are high.
Is this the same as an FMEA RPN? It borrows the severity-occurrence-detection structure of FMEA but uses a weighted average rather than a simple product (RPN). The weighting prevents a single mid-range factor from dominating the way multiplication can.
How do I score the detection factor? Rate how hard the hazard is to catch before it causes harm — a high score means the strain is subtle or builds slowly (poor detection), a low score means it is obvious and easily flagged during routine observation.

Last reviewed 2026-05-12.