Contractor Safety Stats: What the Acronyms Mean

February 9, 2023

If you’re evaluating a roofing contractor’s safety on the job, looking at their incident rates is a good place to start. We’re explaining all the acronyms so you can understand the data. After all, what’s the point of metrics if you don’t know what they mean?

TRIR (aka TIR)

The Total Recordable Incident Rate (TRIR) reflects the number of recordable injuries that a contractor experiences in a year per 100 full-time employees. This is calculated by multiplying the number of annual injuries times 200,000 (the number of hours 100 employees working 40 hours per week, 50 weeks per year would work). The simplified explanation of TRIR is that it’s a ratio meant to indicate the number of injuries a contractor’s employees experience in a year.

“Anything above a band-aid response is a recordable injury,” explains Kirk Dighton, Safety Manager, D. C. Taylor Co., Cedar Rapids, IA. He provides the following example of a situation where a worker has a foreign body in their eye: “If you take them to a doctor and they’re able to remove it with a cotton swab and nothing else, that’s first aid. If they have to remove metal from the eye via surgery and give antibiotics, that’s recordable.”

The national TRIR averages released by the U.S. Department of Labor’s Bureau of Labor Statistics for the roofing industry are often used as benchmarks by roofing contractors (and customers) to evaluate the effectiveness of safety programs and the consistency of their implementation. The North American Industry Classification System (NAICS) code for roofing contractors is 238160.


Another important safety metric is the Days Away, Restricted, or Transferred (DART) rate. While TRIR can give you a snapshot of the number of work-related injuries, it falls short in indicating their severity; that’s where DART comes in. The more serious the injury, the more days a worker will be away from work, the restrictions (think a weight limit on lifting) that will be in place when they return, or the likelihood that duties have been transferred to another individual. DART rate is calculated when you divide the number of injuries and/or illnesses with days away, restricted work or job transfer by the total hours worked by all employees during a calendar year and multiply it times 200,000.


The Lost Time Incident Rate (LTIR) is similar (but more specific) to the DART rate, in calculating the average number of incidents that resulted in an employee being unable to work for a minimum of one day.


The Restricted Time Incident Rate (RTIR), like LTIR, is a more specific measure than DART. It reflects the number of incidents that result in an employee working with specific work restrictions.


Experience Modification Ratio (EMR) was developed by the insurance industry to determine premiums for workers’ compensation insurance. Like the DART rate, it is helpful to gauge the extent of work-related injuries. It reflects the cost associated with recordable safety incidents. A calculation predicts the number of anticipated losses to be paid by the contractor in a designated rating period, taking into account a number of variables. When the expected losses are compared to the actual losses, an experience rating results. A lower EMR indicates that the contractor had fewer and/or less serious incidents than what was expected.

Going Beyond the Numbers

While numbers can give you a snapshot of a contractor’s safety culture, program, and enforcement, they don’t tell the whole story. “Everyone is running relatively lean, so facilities professionals are just looking at the numbers, but they really need to dig deeper,” suggests Dighton. “Roofing work creates a wide variety of hazards. We do very physical work. It’s important to ask roofing contractors not only what they’re doing to keep workers healthy and prevent injuries, but also what corrective actions were taken after an incident occurred.”

Dighton also points out that it can be more difficult for small and mid-size contractors to have low incident rates. “The ratio goes down as you increase your hours,” he explains. “10 injuries are significant, but for a contractor with 1,000 employees nationwide, their rates will still appear low.”

Read about how D. C. Taylor Co. achieved zero safety incidents in 2022 here. Contact us today to schedule your next roofing project at 319.731.4118 or [email protected].

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