By Brian Zaidman, Research Analyst, Research and Statistics, Minnesota Department of Labor & Industry Reprinted from "Safety Lines: The Newsletter of Minnesota OSHA," Spring 2006.
Editor's note: This is the seventh installment of a series about using the OSHA Form 300 and summarizing its results. This
information is directed to people who are new to OSHA recordkeeping activities, who are unfamiliar with the 2002 recordkeeping
changes or who want to review their recordkeeping practices. Visit www.minnesotasafetycouncil.org/MO/articles.cfm for previous
This installment explains how to use log summary
results to track your company’s performance and
to benchmark your rates with state and national
results for your industry. The previous installment
of this series discussed how to complete an annual
log summary (OSHA form 300A). Computing the
incidence rates gives those who are responsible for
workplace safety some perspective about safety
and health issues and a broad measure of the
performance of safety processes. It also helps in
setting goals and prioritizing safety activities for
the coming year.
Data available from the log summary
When you have accurately completed your OSHA
log summary, you have annual numbers for:
Add the number of cases to produce the number of
total recordable cases.
- hours worked by all employees;
- cases with days away from work;
- cases with job transfer or restriction; and
- other recordable cases.
You should also have your North American
Industry Classification System (NAICS) code.
This is necessary if you want to compare your
rates to the corresponding state and national rates.
To find an NAICS code or convert a SIC code to a
NAICS code, visit www.census.gov/epcd/naics02.
Call the Minnesota Department of Employment
and Economic Development at (651) 297-2242 to
get your firm’s NAICS designation.
Computing incidence rates
The number of cases are converted into incidence
rates to show the relative level of injuries and
illnesses, which can be used to compare with rates
of other firms. The most widely used incidence
rate measures are the:
Incidence rates are expressed as the rate of cases
per 100 full-time-equivalent (FTE) workers. An
FTE is defined as one employee working for 40
hours a week for 50 weeks, resulting in 2,000
work hours. One hundred FTEs is equal to 200,000
- total case incidence rate;
- rate of cases with days away from work;
- rate of cases with job transfer or restriction;
- the DART rate, which combines the cases with
days away from work and cases with job
transfer or restriction.
Rates are calculated by first computing the number
of cases per work hour at your firm (divide the
relevant case count by the number of hours
worked). Multiply the result by 200,000 to convert
it to a rate per 100 FTEs.
To assist you in this process, the U.S. Bureau of
Labor Statistics (BLS) has produced an instructive
document, How to compute a firm’s incidence rate
for safety management. It is available online at
BLS rate calculator tool
Fortunately, BLS has a Web tool, the Incidence
rate calculator and comparison tool, that performs
these calculations and provides the comparison
benchmark rates you need. The tool can be
accessed online at http://data.bls.gov/IIRC.
Using and preserving your rates
- Steps 1 and 2 of the tool ask you to input
numbers from your log summary and the total
number of recordable cases.
- Step 3 of the tool allows you to select the
comparison jurisdiction and industry.
- First, select an area, either the entire United
States or an individual state, indicating
whether you want private-sector or publicsector
results. Only the states that participate
in the BLS Survey of Occupational Injuries
and Illnesses are listed.
- Next, select a NAICS supersector, the broad
industry category that describes your firm’s
work. Selecting a supersector changes the
industry list to show you the available
options for your benchmarking rate.
- Then select the industry with the NAICS
code most similar to your firm’s code. This
is usually an industry with the same first
- In Step 4, click on the calculate button. Rates
for your firm and the corresponding rates for the
comparison jurisdiction industry will be
displayed in the results. Below is an example of
what the results table looks like.
The real power of incidence rates lies in observing
the rate trends. Firms’ incidence rates often
display much year-to-year fluctuation, so longerterm
trends are necessary to see what is really
happening. The BLS rate calculator tool only
allows you to generate one year’s set of rates at
|Where do comparison rates come from?
The U.S. Bureau of Labor Statistics (BLS)
and most states conduct the annual Survey
of Occupational Injuries and Illnesses. Based
on size and industry, a random sample of
fi rms is selected each year to participate in
the survey. These firms transfer their log
summary information to a survey form that
is returned to state or regional BLS offi ces.
These summaries are used to compute state
and national incidence rates. The survey is
completely confidential and is used for statistical
purposes only. In Minnesota each year, about
5,000 firms participate in the survey.
|Area: ||Private industry, Minnesota
|Industry: ||Metalworking machinery manufacturing
|Case type || Your establishment || Private industry, Minnesota
|Total || 10.3 || 6.1
|Days away || 2.6 ||1.6
|Job transfer/restriction ||1.7 || 0.9
|DART ||4.3 ||2.5
Federal OSHA recordkeeping resources
MNOSHA recordkeeping resources
MNOSHA WSC recordkeeping training
Survey of Occupational Injuries and Illnesses
Packet of recordkeeping forms, instructions
Booklet: Minnesota OSHA recordkeeping requirement