General

The data on occupational injuries and diseases contained in the National Workers' Compensation Statistics database have been compiled by the National Occupational Health and Safety Commission (NOHSC) from information supplied by Commonwealth, State and Territory workers' compensation authorities. These agencies processed workers' compensation claims received from insurance companies, self-insurers and some government departments. Most of the data supplied accorded with the recommendations of the National Data Set for Compensation-based Statistics (NDS). The data are generally the latest available from each jurisdiction.

The denominators used to derive incidence and frequency rates were calculated by the Australian Bureau of Statistics (ABS) using data from two of their collections, the Labour Force Survey and the Survey of Employee Earnings and Hours.

Scope and Coverage

The National Workers' Compensation Statistics database is comprised of claims for workers' compensation made under the Commonwealth, State and Territory workers' compensation Acts which resulted in a fatality, permanent disability or a temporary disability resulting in an absence from work of one week (5 working days) or more.

The statistics do not cover all occurrences of occupational injuries and diseases for the following reasons:

• data for the Australian Capital Territory are not available;
• temporary disability occupational injuries resulting in absences from work of less than one week (5 working days) have not been included;
• only cases compensated under general Commonwealth, State and Territory workers' compensation legislation are included. Excluded, therefore, are occurrences covered under separate legislation for specific groups of workers;
• military personnel within the defence forces are not included;
• cases not claimed as workers' compensation or not acknowledged as being a work-related injury are excluded; and
• most occupational injuries to the self-employed are excluded because such workers generally are not covered for workers' compensation. (Note: the exclusion of self-employed persons is likely to result in an understatement of the number of occurrences for industries where self-employed persons are common, for example, Agriculture, Forestry and Fishing, Construction, Road Transport and Retail Trade. Nevertheless, incidence and frequency rates data are more reliable as the denominators used in the calculation of the rates have been adjusted to also exclude self-employed persons. Moreover, the type of occurrence data should be broadly representative of the industry experience as a whole).

Incidence and Frequency Rates

The incidence rate of occupational injuries and diseases is the number of occurrences expressed as a rate per 1,000 wage and salary earners employed. Such rates were calculated using the following formula:

• number of occupational injuries and diseases   X   1,000
  number of wage and salary earners

The frequency rate of occupational injuries and diseases is the number of occurrences expressed as a rate per million hours worked by wage and salary earners. Such rates were calculated using the following formula:

• number of occupational injuries and diseases   X   1,000,000
  number of hours worked

Fatalities Data

Caution should be used in interpreting fatalities data as workers' compensation coverage of fatalities has some deficiencies, for example where there are no heirs to lodge claims or in the case of long latency diseases. In addition, jurisdictions do not apply a standard definition as to what constitutes a compensable fatality.

Type of Occurrence Data

Details of the "description of the occurrence" reported on the workers' compensation claim have been coded according to the Type of Occurrence Classification System.

The four classifications used to describe the type of injury or disease sustained by the worker and the way in which it was inflicted are:

• Nature of Injury/Disease;
• Bodily Location of Injury/Disease;
• Mechanism of Injury/Disease;
• Breakdown Agency.

The nature of injury/disease refers to the most serious injury or disease sustained or suffered by the worker.

The bodily location of injury/disease refers to the part of the body affected by the most serious injury or disease.

The mechanism of injury/disease is the action, exposure or event which is the direct cause of the most serious injury or disease, that is, how exactly the injury or disease was sustained.

The breakdown agency refers to the object, substance or circumstance that was principally involved in, or most closely associated with, the point at which things started to go wrong, and which ultimately led to the most serious injury or disease.

The following example is given to assist in explaining the above terms using the description of occurrence reported on workers' compensation claim:

A forklift truck ran into a stack of wooden crates causing them to fall onto a worker resulting in severe lacerations to the worker's face and chest and a minor fracture to the forearm.

The first step in the coding process requires the identification of the most serious injury or disease. The "severe lacerations to the face and chest" carries the potential of permanent facial disfigurement and therefore, that should be identified as the most serious injury, indicating that the nature of injury should be "open wound not involving traumatic amputation" (code 080).

The bodily location of injury code should be determined by the most serious injury. The bodily location of injury, therefore, should be identified as "head and other" (code 630).

The mechanism of injury is also related to the most serious injury sustained. From the information contained in the description, the injury was sustained through the crates falling on the worker. Therefore, the appropriate mechanism of injury is "being hit by falling objects" (code 21).

Determination of the breakdown agency is dependent on the identification of when things started to go wrong. From the description, it is when the forklift ran into the stack of crates that things started going wrong. The product, process or equipment that was most closely associated with this event was the forklift itself. Therefore, the breakdown agency should be identified as the forklift, which falls into the category "forklift trucks" (code 158).

It should be noted that the "Other" category used in the type of occurrence graphs and tables does not represent occurrences which have not been fully and/or appropriately classified, but represents the sum of all the remaining categories which, individually, would be insignificant.

Duration of Absence

Information relating to duration of absence from work should be examined with caution for the following reasons:

• the total duration of the period off work for the more serious cases reported in any one year may not be known for some time after the close off date (updated information for duration of absence will be supplied by jurisdictions for these more serious cases covering a period of two years after the reference year which should improve the utility of these data considerably and enable more valid jurisdictional comparisons of data from previous years); and
• differences in the scope of data collections in some jurisdictions, associated with the effect of employer excess on threshold provisions, may impact on the number of short duration claims reported.

Time-series Comparisons

Comparison of data for the most recent year with previous periods' data should be undertaken with caution. There is variation in the methods employed by the various jurisdictions to process claims and jurisdictions have not always been able to provide claims data at precisely the same point in time.

Moreover, in analysing trends over time, consideration needs to be given to the extent to which jurisdictional-specific legislative changes have occurred during the period concerned and are reflected in movements in number, incidence and frequency rates from year to year.

Not Stated

Several jurisdictions had insufficient information to allocate appropriate codes for a number of data items. In these cases the code for "Not Stated" was assigned.

Reliability of Data

The data are subject to both non-sampling and sampling errors.

Non-sampling Error

Non-sampling errors may affect both the numerator and denominator data. These errors may occur because of errors in the reporting, recording and processing of data. Non-sampling errors may occur in any statistical collection.

Non-sampling errors can occur as a result of the following:

1. deficiencies in the forms used to collect data;
2. incorrect recording of answers by the respondent or the processing agency;
3. inaccurate coding;
4. non-response or omitted cases;
5. errors in collection procedures; and
6. errors in data entry, editing and processing.

It is difficult to measure the size of the non-sampling errors. Their size may vary from collection to collection and even within a collection from data item to data item. Nevertheless, the agencies collecting and processing data attempt to minimise as far as possible non-sampling errors through various means, for example, editing data for accuracy, consistency and comparability.

Sampling Error

The denominator data used in the calculation of incidence and frequency rates are the only data in this database which are subject to sampling error.

The sampling error is a measure of the variability that occurs by chance because a sample, rather than the entire population, is surveyed. One measure of the likely difference is given by the standard error, which indicates the extent to which an estimate might have varied by chance because a sample was selected. Sampling variability is also measured by the relative standard error, which is obtained by expressing the standard error as a percentage of the estimate to which it refers.

Incidence and frequency rates with high relative standard errors (greater than 50%) have not been included in the tables, graphs or analysis.

The denominator data used in the calculation of the rates data were derived in accordance with the methodology developed by the Australian Bureau of Statistics (ABS). The ABS estimated the denominator data from two of their collections: the Monthly Labour Force Survey and the Survey of Employee Earnings and Hours. The Monthly Labour Force Survey data have been adjusted to exclude Commonwealth employees, as identified in the Survey of Employee Earnings and Hours.

The way in which the denominators were calculated limits the level of analysis possible for incidence and frequency rates. In addition, those rates relating to jurisdictions with relatively small numbers of persons employed should be viewed with caution.

Users with technical queries about the methodology used to estimate the denominator data or about the sampling errors associated with the data should contact the Labour Force Sub-section, Australian Bureau of Statistics
PO Box 10, BELCONNEN ACT 2616, telephone (02) 6252 6525.

Confidentiality

Reports produced on this database have been adjusted to ensure adherence to NOHSC confidentiality practices. This includes the suppression of small cell values and random adjustments which have been applied to all individual cell values to ensure that confidential information about employers and employees is protected. For this reason, and because of the effect of small differences between the data supplied, differences will occur between the totals and the sum of the row and column values and between tables (these differences can be either positive or negative). It should be noted that information relating to individual fatalities has not been treated as confidential, by agreement with the data suppliers, as this information is a matter of public record.

Definitions

The terms "occupational injuries" and "occupational diseases", as defined in the NDS are repeated below. Their use and definitions are in accordance with the resolutions of the Thirteenth International Conference of Labour Statisticians, October 1982.

Occupational Injuries

All employment injuries whic h are the result of a single traumatic event occurring while a person is on duty or during a recess period and where there was a short or non-existent latency period. This includes injuries which are the result of a single exposure to an agent(s) causing an acute toxic effect.

Occupational Diseases

All employment injuries which result from repeated or long term exposure to an agent(s) or event(s), and employment injuries which are the result of a single traumatic event where there was a long latency period, for example, the development of hepatitis following a single exposure to the infection. It should be noted that workers' compensation data are not an ideal measure of the extent of work-related disease as many disease occurrences do not result in compensation claims for a variety of reasons.

Industry

The industry within which the occupational injury occurred was classified in accordance with the ABS classification, the Australian and New Zealand Standard Industrial Classification (ANZSIC), 1993 edition (ABS Cat. No. 1292.0).

Occupation

The occupation of the injured worker was classified in accordance with the ABS classification, the Australian Standard Classification of Occupations (ASCO2), First Edition, September 1986 (ABS Cat. No. 1222.0).

NOHSC Website

More statistical data and information on a range of OHS-related topics is available through the NOHSC website. The web address is:

http://www.nohsc.gov.au

Symbols Used

The following standard symbols are used:

Email: