Are all reported Injury Rates (IRs) equivalent?

I look at a lot of reports and see a wide variation in the reported injury rates among what should be similar jurisdictions. What accounts for these differences? In some cases, there are wide differences in the ‘mix’ of industries covered. You can expect a jurisdiction with a large service sector and small primary resources and construction sectors to have a lower injury rate than one dominated by construction, mining and forestry. That aside, variability can also have a lot to do with definitions.

The AWCBC reports an Injury Frequency statistic based on the following definition:

Number of new lost-time claims for assessable employers per 100 workers of assessable employers

Note the definition depends on what is counted in the numerator (lost-time claims) and what is used as the denominator (workers of assessable employers). AWCBC also defines Lost-time Claims in this way:

A lost-time claim is a claim where an employee is compensated for a loss of wages following a work-related injury (or exposure to noxious substance), or receives compensation for a permanent disability with or without any time lost in his or her employment (for example, if an employee is compensated for a loss of hearing resulting from excessive noise in the work place).

So, another source of variability is in what is reported as compensated. If a jurisdiction has a waiting period or actively promotes ‘stay at work’ programs, claims involving loss of wages will be lower in that jurisdiction than in a similar jurisdiction without a waiting period or significant stay-at-work program.

In a previous blog, I noted the difference in reporting requirements. In addition to those issues, the source of the statistic also needs to be considered. In the US and Europe, most published data is based on Occupational Safety and Health data. In the US, OSHA has specific definitions for what is reportable and these ultimately have an impact on the reported IR. Further, within the reportable cases, there is a distinction between ‘days away from work’ cases and those where ‘alternate duties’ are assigned. While most workers have workers’ compensation coverage in the US, most published IRs are not based on claims.

At WorkSafeBC we report a Provincial Injury Rate in accordance with the AWCBC definition. For BC, where 93% of the employed labour force is covered, this is a pretty reasonable estimate of the provincial IR. Note, however, that it reflects assessable employers only. It does not include, for example, the injuries that occur within the Provincial Government public service as the Provincial Government is not an assessable employer. In provinces with lower covered populations and higher proportions of non-assessed employers, what is reflected in the IR may be far less representative of the provincial injury rate.

Finally, the IR that is reported in some other jurisdictions excludes from the numerator claims (or work absences) of very short duration. WorkSafeBC’s Injury Rate is an IR0 (claims involving at least some wage loss) and the US generally uses IR0 (reportable cases involving days of work absence) although some reports use IR3. In Australia, where one week of work absence is the threshold for a claim in most jurisdictions, their reported claim rates would be equivalent to IR5 or IR7 (depending on the basis for compensation being 5 or 7 days).

So, when you are looking at injury rates in other jurisdictions, dig a little deeper and understand the inherent differences before drawing any conclusions. For the record, WorkSafeBC’s Injury Rates are as follows:

IR0: 2.34, IR3: 1.75, IR5: 1.50, IR7: 1.35 (In the 2009 Annual Report, the Provincial Injury Rate [IR0] is reported as 2.37, the best estimate available at the time of publication).