Key points
- Follow up to make sure your interventions work.
- Measure effectiveness by comparing data before and after.
- Calculate the payback and return on investment (ROI) to show the program's value.
This is the fifth step of NIOSH's guide to workplace ergonomics programs.
Follow up
Check that the controls you put in place really reduce or eliminate the risk factors for work-related musculoskeletal disorders (WMSDs) — and that they didn't create new ones.
- Expect some soreness. Workers doing a job differently may use new muscle groups. Check with them after one week and again after one month.
- Allow for conditioning. New employees and people returning after a long absence need about two weeks to condition their muscles, especially for highly repetitive tasks such as paced work on a fast conveyor or picking items to a time standard. Soreness during that period is to be expected.
- Be patient. Old WMSD symptoms can take months to disappear. If new symptoms appear, change the intervention.
Measure effectiveness
Compare these before and after the intervention:
| Administrative data | Results data |
|---|---|
| job analyses | productivity indicators |
| checklists | quality of products and services |
| symptom surveys | total savings |
| OSHA Form 300 logs | |
| absentee rates | |
| turnover rates | |
| workers' compensation costs |
Three ways to put a number on it
| Measure | Formula | What it tells you |
|---|---|---|
| Benefit-cost ratio | worth of benefits ÷ worth of cost | Above 1, the benefits outweigh the cost; equal to 1, break-even; below 1, the cost outweighs the benefits |
| Cost-benefit (payback period) | cost ÷ total savings per year | How long savings take to repay the investment, counting injuries prevented |
| Return on investment (time) | initial cost ÷ savings per time interval | How long it takes to recover the initial cost from a single saving, such as time |
The source phrases the ratio test as greater than, equal to or less than "the investment"; for a ratio of benefits to cost, the break-even point is 1.
Worked example: a metals recycler
A metals recycling company runs production 365 days a year. Workers lift scrap by hand to load a forklift, which risks injury. It considers replacing the loading dock system with two new scrap conveyors, installed for a total of $53,800.
Savings from injuries prevented — compensation claims avoided:
- sprains: $30,000
- back strain: $33,000
- total: $63,000 a year
Savings from time. The new system saves 3 hours a day, and employees earn $23 an hour:
- 3 hours/day × $23/hour = $69 a day
- $69/day × 365 days/year = $25,185 a year
Payback, counting injuries and time:
- total benefit: $63,000 + $25,185 = $88,185 a year
- $53,800 ÷ $88,185 a year = 0.61 year, about 7.3 months
Return on investment, counting time alone:
- $53,800 ÷ $69 a day = 780 days, about 2 years 50 days
Injury prevention is what makes the conveyors pay for themselves in months rather than years.
Resources
- NIOSH: Workers' Compensation Insurance: A Primer for Public Health
- NIOSH: How to Evaluate Safety and Health Changes in the Workplace
- NIOSH: Guide to Evaluating the Effectiveness of Strategies for Preventing Work Injuries
- OSHA: Business Case for Safety and Health and the Safety Pays estimator
- Cornell University: Return on Investment Calculator
- National Safety Council: Journey to Safety Excellence — the business case
- EU-OSHA: The business case for safety and health at work
Sources
Based on "Step 5: Evaluate Your Ergonomic Program," National Institute for Occupational Safety and Health (NIOSH), CDC. Its equations, published as images, are set here as text from the archived page. A work of the United States government in the public domain.
Licence: CC0 1.0 (public domain) · Adapted from www.cdc.gov
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