Crime statistical notes

Accurate statistics

In recording and reporting crime data there are numerous internal 'checks and balances' in place throughout the various stages of the process, culminating in an annual audit conducted by the Office of the Auditor General.

Comprehensive statistics

The majority of publications that contain Western Australian crime statistics do so only at the state level and with respect to limited offence classifications. This website contains statistics for a broad range of offence categories at the state, region and district levels as well as providing access to statistics for six selected offence groups at the suburb or locality level.

Current statistics

Generally, Western Australian crime statistics have been published either on an end of financial year or calendar year basis. This website includes monthly statistics that are updated on a monthly basis.

As of March 2007, the Western Australia Police updated the process whereby official crime statistics for reported and cleared offences were produced. Instead of each month's data being extracted one month at a time, the new process involves extracting and reporting on the current month as well as updating the previous 12 months. As a consequence, each time new figures are posted on the WA Police website (or in any other forum) previously published and available statistics may be updated. All statistics are therefore provisional and subject to revision for a period of one year.

Environmental Context - The incidence of crime is not generally within the control of the police. However, it should be noted that pro-active policing and educational strategies, such as encouraging the community to report incidents of domestic violence and sexual assault, and targeted policing strategies, such as increased and concentrated police activities associated with detecting illicit drugs, may have a significant impact on the number of offences recorded.

Explanatory Notes

1. The crime statistics provided on this website are preliminary and subject to revision.

2. Offences are classified according to WA Police offence codes. Offence descriptions have been included on this website to assist readers in understanding how offences are classified.

3. Offence classifications may alter between periods due to changes in legislation or administrative recording practices. Accordingly, time series may be broken.

4. Crime statistics are provided for selected offences reported to, or becoming known to police and resulting in the submission of an offence/incident report in WA Police systems. The statistics exclude offences against public order, such as disorderly conduct and offences against the Firearms Act 1973, Liquor Licensing Act 1988 and a number of other offences against the statute laws of this State and the Commonwealth.

5. The number of offences recorded in a period is determined by the date the offences were reported, not the date the offence was committed. Accordingly, offences reported may not have been committed during the reporting period and data may be affected by the reporting of historical offences, such as the reporting of past sexual offences.

6. From late 2002, a number of factors have affected victim reporting and police recording of offence and clearance statistics. For example:

  • Due to recording issues associated with the offence category of 'driving causing death', this category has been removed and all 'driving causing death' offences have been incorporated within the offence category of 'manslaughter'.
  • Coding and recording issues associated with the offence categories of 'aggravated and non-aggravated sexual assault' have had an impact on the number of sexual assault offences recorded.
  • Due to recording issues associated with the offence category of 'assault police officer', this category has been removed and all 'assault police officer' offences have been incorporated within the offence category of 'non-aggravated assault'.
  • Recording issues and reporting practices by some Government agencies, local government authorities and private enterprise associated with certain offence categories such as 'fraud' and 'graffiti' impact on the number of offences recorded.
  • Definitional, coding and processing changes associated with the introduction of the FrontLine Incident Management System have had an impact on some data.

Accordingly, caution should be exercised when interpreting and using offence and clearance statistics from late 2002, especially when comparing those statistics with earlier periods. For example, any variation may not necessarily reflect an actual increase or decrease in the incidence of an offence type (or in total offence numbers), but rather variations resulting from reporting and recording changes. The clearance of offences is similarly impacted upon.

Note that due to the inclusion of 'driving causing death' offences under the offence category of 'manslaughter' and 'assault police officer' offences under the offence category of 'non-aggravated assault', it is not possible to compare offences and clearance rates shown against the offence categories of 'manslaughter' or 'non-aggravated assault' contained in the 2003-04 and subsequent financial year Tables with manslaughter and non-aggravated assault statistics shown in Tables for earlier financial years.

7. 'Steal motor vehicle' excludes attempts to steal a motor vehicle, damaging or tampering/ interfering with a motor vehicle, or the theft of motor vehicle parts or the contents of a motor vehicle. For the purpose of this offence category, a motor vehicle is defined as a self-propelled vehicle that runs on a land surface (but is not restricted to rails or tram lines) and is eligible for registration for use on public roads, or could be made eligible for registration for use on public roads with modifications that would not change the essential nature of the vehicle. 'Steal motor vehicle' therefore excludes the theft of some types of motorised vehicle such as large mining trucks (super-haulers), gophers (motorised wheel chairs), golf carts, miniature motor cycles (pocket rockets), go carts and motorised bicycles/scooters, and also excludes the theft of trailers, semi-trailers or caravans (regardless of whether or not they were attached to a motor vehicle at the time of theft).

8. The number of offences cleared in a period is determined by the date clearances were recorded. Due to the nature and length of investigations, the number of offences cleared during the reporting period may include offences reported prior to that period. The clearance rate is based on the number of offences cleared during a period expressed as a percentage of the number of offences reported during the same period. The clearance rate may exceed 100 per cent due to more offences being cleared than were reported during a reporting period.

9. An offence is cleared (clearance) where an offender(s) is apprehended or processed (such as by arrest, summons, Juvenile Justice Team referral, juvenile caution, drug caution or infringement) or where, for some substantial reason, police investigations cannot be continued. These reasons include:the offender has died; the offender is in another jurisdiction and extradition is not desired or available; insufficient evidence exists to proceed against a suspect; there is a statute bar to proceedings where an offender is under age or claims diplomatic immunity; admittance to a psychiatric facility; false or mistaken reports; withdrawn complaint; civil action recommended.

10. Clearances are attributed according to the locality in which the offence occurred, not the locality at which the offence was cleared.

Statistical Analysis

For statistical analysis on the incidence of crime and crime trends in Western Australia, reference can be made to the following information sources:

  • Western Australia Police Annual Report

  • Australian Bureau of Statistics publications:

    • Recorded Crime Australia (catalogue no.4510.0) - this document contains annual national reported crime trends.
    • Crime and Safety Australia (catalogue no. 4509.0) - this document describes the results of victimisation surveys, the last national survey being in 2005. A separate WA Crime and Safety survey was last conducted in 2000 (results published in WA Statistical Indicators March 2001 - catalogue no. 1367.5).
    • Western Australian Statistical Indicators (catalogue no. 1367.5) - this document contains selected reported offences by quarter for WA and statistical regions.
    • Personal Safety, Australia, 2005 (catalogue no. 4906.0) - this document presents information about men's and women's experience of physical or sexual assault or threat by male and female perpetrators.
    • Personal Safety, Australia, 2005 (catalogue no. 4906.0) - this document presents information about men's and women's experience of physical or sexual assault or threat by male and female perpetrators.
    • Home Safety and Security, Western Australia, October 2004 (catalogue no. 4526.5.55.001) - this document presents information on safety measures, security features, break-ins and attempted break-ins in Western Australian households.
    • Sexual Assault in Australia: A Statistical Overview, 2004 (catalogue no. 4523.0) - this document presents statistics that provide a broad overview of sexual assault in Australia. It includes data from selected ABS and other sources, as well as commentary to describe the prevalence and incidence of sexual assault, individual experiences, responses provided and resultant outcomes.

  • Crime and Justice Statistics for Western Australia produced by the University of Western Australia Crime Research Centre. This annual document contains statistical information on crime and the WA Criminal Justice System. It also contains maps showing the incidence of crime by suburb.