How To Compute a Firm's Incidence Rate for Safety Management
Incidence rates can be used to show the relative level of injuries and illnesses among different industries, firms, or operations within a single firm. Because a common base and a specific period of time are involved, these rates can help determine both problem areas and progress in preventing work-related injuries and illnesses. The Bureau of Labor Statistics (BLS) has developed these instructions to provide a step by step approach for employers to evaluate their firm's injury and illness record.
BLS also has a new online calculator that makes it easy to compute incidence rates for your establishment and to compare them to your industry's averages.
How to compute incidence rates
(a) The number of nonfatal injuries and illnesses. This number is available several ways:
(b) The number of hours all employees actually worked. "Hours worked" should not include any nonwork time, even though paid, such as vacation, sick leave, holidays, etc. If actual hours worked are not available for employees paid on commission, by salary, or by the mile, etc., hours worked may be estimated on the basis of scheduled hours or 8 hours per workday. This number is also available from several sources:
An incidence rate of injuries and illnesses may be computed from the following formula:
(Number of injuries and illnesses X 200,000) / Employee hours worked = Incidence rate
(The 200,000 hours in the formula represents the equivalent of 100 employees working 40 hours per week, 50 weeks per year, and provides the standard base for the incidence rates.) You can use the same formula to compute incidence rates for:
How are incidence rates used?
Incidence rates take on more meaning for an employer when the injury and illness experience of his or her firm is compared with that of other employers doing similar work with workforces of similar size. Information available from BLS permits detailed comparisons by industry and size of firm.
The following tables illustrate how detailed comparisons can help a firm evaluate its safety and health experience more precisely.
In this example, the injury and illness rates for ABC Company are below the industry wide and similar-size averages for construction machinery manufacturers.
Information available from BLS goes beyond giving the average incidence rate for a particular industry and employment-size class: Data show how individual establishment rates within an industry-size combination are distributed.
Points on these rate arrays, called the first quartile, median, and third quartile, help answer the following question: What proportion of comparable employers have rates that are lower than (or higher than) my firms rates? The following table for construction machinery manufacturer firms employing 50 to 249 workers illustrates how these statistical measures work.
When ABC Company extends its rate comparison to these measures, the company finds that its total recordable rate (7.5) falls between the first quartile rate and the median rate for construction machinery manufacturers of similar size, and its rate for cases with days away from work, job transfer, or restriction (3.5) falls between the corresponding first quartile and median rates for construction machinery manufacturers of similar size. In other words, both of ABC Companys rates are lower than the rates for at least one-half of the medium-size construction machinery manufacturers. This analysis reinforces earlier findings that ABC Company has a lower incidence rate of injury and illness in its workplace than do most other construction machinery manufacturers of its size.
How do I obtain industry-specific data?
2006 incidence rates by quartile distribution and employment size group for:
Total recordable cases of injuries and illnesses (TXT) (PDF 229K)
Last Modified Date: October 16, 2007