 # Math for Safety Professionals

OSHA Recordable Incident Rate The OSHA Recordable Incident Rate (or Incident Rate) is calculated by multiplying the number of recordable cases by 200,000, and then dividing that number by the number of labor hours at the company.

 IR = Number of OSHA Recordable Cases x 200,000 Number of Employee labor hours worked

Lost Time Case Rate (LTC)

The Lost Time Case Rate is a similar calculation, only it uses the number of cases that

contained lost work days. The calculation is made by multiplying the number of incidents

that were lost time cases by 200,000 and then dividing that by the employee labor hours at

the company.

 LTC Rate = Number of Lost Time Cases x 200,000 Number of Employee labor hours worked

DART Rate (Days Away/Restricted or Job Transfer Rate)

The DART rate is relatively new to industry. This rate is calculated by adding up the

number of incidents that had one or more Lost Days, one or more Restricted Days or that

resulted in an employee transferring to a different job within the company, and

multiplying that number by 200,000, then dividing that number by the number of

employee labor hours at the company.

 DART Rate = Total Number of Dart Cases x 200,000 Number of Employee labor hours worked

Severity Rate (SR)

The severity rate is a calculation that gives a company an average of the number of lost

days per recordable incident. Please note, that very few companies use the severity rate as

a calculation, as it only provides an average. The calculation is made by dividing the total

number of lost workdays by the total number of recordable incidents.

 SR = Total number lost workdays Total number of recordable incidents