# Occupational (OSHA) and Environmental Hazards/partial year incident rate calculations

Question
You've answered several questions regarding calculating incident rates for partial year.  In one, you included in your reply "Some of the confusions comes from the habit people have of not giving the units involved. People, firms and even the government state an Incident Rate of 5.2 and not the correct which is an "Incident Rate of 5.2 Recordable Incidents per 100 Employees".

Isn't the correct unit "recordable incidents per 100 employees PER YEAR"?  The 200,000 hour factor is the amount of hours worked by 100 employees in ONE YEAR.

If someone want to calculate a partial year incident rate, such as for just one quarter, shouldn't they compare their hours worked in that quarter to that worked by 100 employees in one quarter and not the whole year?  If an employer had 200 employees and 2 got injured, using the 200,000 factor would give a per annum rate of 4.  If they continued to  hurt 2 employees every quarter, then the 4 would be correct for the year.  But considering that the year is only 1/4 over, and they really have hurt "only" 1 out of 100, then using 50,000 hours should be used #that is the number of hours worked by 100 people in one quarter#.

If the company only worked one quarter per year, then sure, use 200,000 as the factor.  But on a accumulated basis through the year, shouldn't the same time period be used to calculate the hours worked by the employees and the hours worked by the "100 employees"?

Subject: Partial year incident rate calculations

Question: You've answered several questions regarding calculating incident rates for partial year.  In one, you included in your reply "Some of the confusions comes from the habit people have of not giving the units involved. People, firms and even the government state an Incident Rate of 5.2 and not the correct which is an "Incident Rate of 5.2 Recordable Incidents per 100 Employees".

Isn't the correct unit "recordable incidents per 100 employees PER YEAR"?  The 200,000 hour factor is the amount of hours worked by 100 employees in ONE YEAR.

If someone want to calculate a partial year incident rate, such as for just one quarter, shouldn't they compare their hours worked in that quarter to that worked by 100 employees in one quarter and not the whole year?  If an employer had 200 employees and 2 got injured, using the 200,000 factor would give a per annum rate of 4.  If they continued to  hurt 2 employees every quarter, then the 4 would be correct for the year.  But considering that the year is only 1/4 over, and they really have hurt "only" 1 out of 100, then using 50,000 hours should be used #that is the number of hours worked by 100 people in one quarter#.

If the company only worked one quarter per year, then sure, use 200,000 as the factor.  But on a accumulated basis through the year, shouldn't the same time period be used to calculate the hours worked by the employees and the hours worked by the "100 employees"?

Answer: Yes, technically it is injuries per 100 employees per year, but in most cases this is covered by stating "the 2012 OSHA Incident Rate was x.xx recordable injuries per 100 employees" which implies the period was one year - that year being 2012. Convention does not favor part of the 200,000 being used or else it would be had to conduct comparisons. (Not that most are worth the paper they are written upon.) The 200,000 is a firm constant set by OSHA and used by most companies and agencies I am familiar with. I would not blame OSHA for this method as it is a refinement of the old "accident Frequency" rates (based on 1,000,000 hours) used by the National Safety Council in the pre-OSHA years. At my last employer we reported and calculated incident rates on a monthly, quarterly and annual basis and still used the constant of 200,000 for each. If someone wanted to use a different method there are no rules that would prohibit is but it would be out of "step" with most industries. If you have any further questions, please feel free to ask.

Michael Brown, CSP Retired

Questioner's Rating
 Rating(1-10) Knowledgeability = 10 Clarity of Response = 10 Politeness = 10 Comment Wow, thanks for the VERY quick reply.

Occupational (OSHA) and Environmental Hazards