What is the formula for calculating the Injury Severity Rate (IRS)?

The formula for calculating the Injury Severity Rate (IRS) is indeed (Lost workdays x 100,000) / Total employee hours of exposure. This formula effectively provides a measure of the severity of injuries in the workplace by taking into account both the number of lost workdays due to injuries and the total hours worked by employees.

Using lost workdays as the numerator allows organizations to quantify how severe the injuries are, since longer recovery times (more lost workdays) indicate more serious injuries. The multiplication by 100,000 standardizes the measure, making it easier to compare across different organizations or time periods. This standardization helps to reflect the severity of injuries in relation to the overall exposure or risk level of employees, which is represented in the denominator by the total employee hours of exposure.

This approach is essential for employers focusing on improving workplace safety since it not only reflects injury frequency but also the impact of those injuries on productivity and workforce availability. A clear understanding of the IRS can assist in identifying trends, facilitating safety improvements, and ultimately fostering a safer working environment.