WA data definitions and calculations

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This page will help you to understand some of the statistical definitions that WorkSafe uses and how some of the benchmark calculations are performed.

The data

The data, provided to WorkSafe by WorkCover WA, is derived from workers’ compensation claims lodged in accordance with the Workers’ Compensation and Injury Management Act 1981. Only those workers who are covered under the Workers’ Compensation and Injury Management Act 1981 (the Act) are included in the data. 

A worker’s compensation claim may be lodged by any person who is a ‘worker’, as defined by section 5 of the Act. This includes working directors who are deemed ‘workers’ under the Act and have some ownership of the company, as well as employed family members and private household workers (for whom workers’ compensation cover is optional). Self employed people, Commonwealth Government workers (including defence service personnel), workers covered by Comcare, police officers (except for work-related fatalities), unpaid volunteers and students on work experience are excluded from workers’ compensation data.

Preliminary data

The latest available year for published lost time injury and disease data is considered a preliminary dataset and is denoted by 'p' or '(preliminary)'. 

This data snapshot is due to the early extraction of claims data for national reporting purposes, resulting in immature claims information. Data revisions will occur for subsequent annual extractions as claims mature or finalised, providing a more stable set of data.

Lost time injury/disease (LTI/D) 

Those occurrences that resulted in a fatality, permanent disability or time lost from work of one day/shift or more.

Note: National lost time injury and disease data (as well as other jurisdictions in Australia) are generally based on workers’ compensation claims where time lost is five days/shifts or more. Other statistical and legislative differences exist between jurisdictions; therefore it is advisable to always read the definitions before making comparisons.

No lost-time injuries/diseases 

Those occurrences which were not lost time injuries and for which first aid and or medical treatment was administered.

Near misses 

Any incidents that occurred at the workplace which did not result in any injury or diseases, but had the potential to do so.

Commuting injuries

All injuries that occurred during travel while not on duty, or during a recess period. This would normally include travel between place of abode and workplace, travel to technical school for training associated with employment and travel to receive medical treatment for an injury sustained at work.

WorkSafe uses lost time injury/disease (LTI/D) figures to calculate rates.

Frequency rate

The frequency rate is the number of lost time injuries and diseases for each one million hours worked. The formula used for calculating frequency rates is: 

Frequency rate = (number of LTI/Ds / number of hours worked) 1,000,000

The number of hours worked is defined as the total number of hours worked by workers covered by the compensation system during this period. The hours worked are usually represented in millions.

Incidence rate 

The incidence rate is the number of lost time injuries and diseases for each one hundred workers employed. The formula used is: 

Incidence rate = (number of LTI/Ds / number of workers) 100

The number of workers is defined as the average number of workers covered by the compensation system who worked during the relevant period. As a result of treating casual, seasonal and part and full-time workers equally, incidence rates can give misleading indications of relative risk. This is relevant to industries with high levels of part-time employment where the number of workers employed may be comparatively high but the actual exposure to hazards (reflected in actual hours worked) may be less.

Frequency rate 60+ Days

The frequency rate 60+ days is the number of lost time injuries and diseases resulting in 60 or more days lost for each one million hours worked. The formula used for calculating this rate is:

Frequency rate = (number of LTI/Ds resulting in 60 or more days lost / number of hours worked) 1,000,000

Incidence rate 60+ Days 

The incidence rate 60+ days is the number of lost time injuries and diseases resulting in 60 or more days lost for each one hundred workers employed. The formula for calculating this rate is:

Incidence rate = (number of LTI/Ds resulting in 60 or more days lost / number of workers) 100

Note that Frequency 60+ days and Incidence 60+ days replace the Severity percentage, which was calculated as Severity = the percentage of LTI/Ds with 60 or more days lost.

Duration

Duration = the average number of working days lost per LTI/D 

Note that this is not a true rate.

Fatality incidence rate

Fatality rate = number of work related fatalities per million workers per year

Data symbol ‘<5’ 

As the data WorkSafe uses is derived from confidential workers’ compensation claims, it is essential that claimants are protected from possible identification. To ensure this, incidences that total less than five are denoted by the data symbol '<5'.

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