Measuring victims of crime: a guide to using administrative and survey data

Provides guidance on the use of administrative data and survey data in the context of crime and justice statistics

Release date and time

Chapter 1 - Introduction

The levels of crime victimisation in the community, as well as people’s perceptions of their safety, are issues that impact directly or indirectly on the quality of people’s lives. Those experiencing direct victimisation in particular, may suffer financially, physically or emotionally. Fear of crime can affect people by restricting community engagement, reducing levels of trust and impacting on social cohesion.

There are a number of ways in which individuals, the community and governments gather information about crime victimisation in Australia. Statistical data is a key component of this information about crime and is critical to decision making, research and policy development.

The suite of statistics produced by the Australian Bureau of Statistics (ABS) has expanded in recent years with the introduction of the redesigned Crime Victimisation Survey in 2008-09 (for further information please refer to Crime Victimisation, Australia cat. no. 4530.0). Faced with a variety of statistical information about crime, it is often difficult for data users to ascertain which data source is best suited for their particular needs. 

Statistics need to be well understood in order for them to be useful in making informed decisions. In some instances results from different data sources may provide a different picture of crime in the community, with administrative data indicating a trend in one direction and survey responses indicating the opposite. The reality is that the different data sources collected via different methods can produce equally valid but quite varied sets of crime victimisation indicators. The challenge for data users is to understand the origins of these different datasets and be able to identify statistics that are most relevant for their needs.

The aim of this paper is to increase community understanding of how the experiences of victims of crime in Australia are measured and to explore why the findings from different data sources may differ. A working example of comparisons between two different data sources is used to demonstrate the impact of varying data collection methodologies on data for a range of offence types. Readers are also offered guidance about which data source is best suited to particular research questions. 

  •  Chapter 2 outlines the available ABS data sources for crime statistics and highlights the main differences between the sources;
  •  Chapter 3 shows a working example of the differences between administrative and survey data using statistics from Crime Victimisation, Australia and Recorded Crime – Victims, Australia;
  •  Chapter 4 provides guidance on the suitability of each data source to answer specific research questions; and
  • A technical note steps through the methodology employed for the analysis provided in chapter 3
     

Chapter 2 - Differences between crime data sources

Introduction

Concepts relating to crime and justice, including victimisation, can be challenging to measure, and the full quantum of crime occurring within the community may never be discovered. One of the key difficulties in determining the true prevalence of crime victimisation within a community is that many victims of crime do not report their experiences to police, and so are not counted in official police recorded data. The reasons for not reporting to the police vary widely, but may be due to the sensitive and personal nature of the criminal offence (for instance, sexual assault or abuse), a belief that the police could not act in response to a victim’s report, fear of reprisal from the offender, simply being too upset or injured following an incident, or wanting to deal with the issue themselves.

There is also a wide variety of information required to effectively describe people’s experiences as victims and answer research and policy questions about crime victimisation. For example, data may be required to:

  • estimate the overall risk of becoming a victim,
  • monitor trends in crime victimisation over time and across different geographic locations,
  • identify risk factors in becoming a victim, to assist in establishing priorities for service providers, such as police and victim support groups, and
  • contribute to understanding long-term outcomes for victims of crime.


There is no single data source that is able to provide all the information required to build a full picture of crime victimisation in Australia. Rather, there are multiple sources of information which provide data on different aspects of victimisation. 

The Australian Bureau of Statistics (ABS) maintains national collections on crime victimisation from two different sources: administrative records, such as data from state and territory police agencies; and household surveys. While the collections contain data about closely related concepts, in practice, survey data and administrative data are quite different, and there are advantages and disadvantages to both methods.

At times, the results from different administrative and survey data sources may create divergent pictures of crime in the community. The purpose of this chapter is to explore the key differences between crime victimisation data sources and discuss the implications of these on data comparability.

Administrative data

Administrative data are produced in the course of providing services to client groups or otherwise undertaking the core business of an agency, and as such are shaped by the business practices and the environment within which the agency is operating. There are key advantages associated with collating statistics from administrative data. Generally, administrative data essentially takes the form of a census, in that all the data recorded through the administrative process is potentially available for statistical analysis. Hence the data are not subject to sampling error which is associated with survey data. Administrative data also has the capacity for ongoing, efficient data collection without incurring much of the additional enumeration cost associated with conducting surveys.

There are also disadvantages associated with using administrative data. Data quality may be variable as there can be conflicting demands on record keepers, and statistics are rarely the primary purpose for which the data are collected. For example, crime data is collected as a by-product of police recording systems, the purpose of which is to assist the police agency in managing its business, rather than collect statistics. Furthermore, definitions of data items may not exactly match the definitions of the data items of interest to others outside of the agency and can make comparability challenging.

Administrative data on crime victimisation can be derived from a number of sources including police, hospitals and community service agencies. The ABS publishes data from two administrative data sources about victims of crime:

Recorded crime - victims, Australia

The annual Recorded Crime – Victims collection presents crime statistics relating to victims of a selected range of personal and household offences that have been recorded by police. These statistics provide indicators of the level and nature of recorded crime in Australia. Data includes a breakdown of the selected offences by victim characteristics (age and sex); the nature of the incident (weapon use and location); and outcome of police investigations at 30 days. Selected state and territory information about the relationship of offender to victim and Indigenous status of the victim is also included.

Data have been provided by state and territory police agencies on a calendar year basis since 1993. A number of standards, classifications and counting rules have been developed since the inception of this collection to improve the national comparability of the data. The National Crime Recording Standard (NCRS) was developed in collaboration with police agencies across Australia and comprises a uniform set of business rules and requirements to guide the recording and counting of criminal incidents. In addition, the Australian and New Zealand Standard Offence Classification (ANZSOC), 2011 (cat. no. 1234.0) provides a uniform national statistical framework for classifying offences.

Statistics from the Recorded Crime - Victims collection are published in Recorded Crime – Victims, Australia (cat. no. 4510.0)

Causes of death, Australia

The annual Causes of Death collection presents statistics and indicators for all deaths (excluding perinatal deaths since 1996) registered in Australia and includes data on sex, selected age groups and cause of death. The statistics are compiled from data made available to the ABS by the Registrar of Births, Deaths and Marriages in each state and territory and by the National Coronial Information System – the latter in relation to deaths referred to a state or territory coroner for investigation. Cause of death is classified to the World Health Organisation’s International Classification of Diseases (ICD). Version 10 of the ICD was introduced from the 1999 reference year and is presented in a number of different ways including: by underlying cause, leading cause and multiple causes.

The category of death through external causes can be further disaggregated to the category of death through assault, which is used as a measure of homicides / manslaughter.

Statistics from the Causes of Death collection are published in Causes of Death, Australia (cat. no. 3303.0).

Comparisons across administrative data sources

Data extracted from the Causes of Death and Recorded Crime - Victims collections will produce different results for similar data items due to a wide variety of factors, such as:

  • when the information is recorded (e.g. recording of an incident as it comes to the attention of the agency or at some later stage after investigation or other formal process);
  • the counting unit used by the agency (e.g. person count or incident count);
  • recording rules (e.g. mandatory reporting of some variables); and
  • the definition of concepts (a legal interpretation of assault may be different to a hospital treatment interpretation of assault).


A comparison between Causes of Death data and Recorded Crime – Victims homicide data found that Recorded Crime – Victims data consistently yielded higher homicide counts when compared to Causes of Death data (Mouzos, 2003). The analysis highlighted possible reasons for this difference including the difference in when the information is recorded. For the Cause of Death data, deaths are classified as homicides based on the coroner’s determination of the final intent of the incident causing death, whereas Recorded Crime – Victims data is based on the initial recording of criminal incidents by state and territory police agencies. In addition, homicide counts derived from the Cause of Death data are based on year of death registration whereas Recorded Crime – Victims homicide data are based on the year that the homicide becomes known to police.

Comparisons within administrative data

When collating national data from various state and territory agencies (e.g. state/territory police agencies), differences may also occur between states and territories due to factors such as:

  • differences in legislation between states and territories;
  • differences in recording practices between relevant state/territory agencies (e.g. police);
  • differences in local standards and classifications that may impact on the ability to map to official statistical standards;
  • differences in the IT systems used to capture information; and
  • differences in data extraction methods.


While the application of national standards and classifications help to minimise the differences between state and territory data, differences in business rules, procedures, systems, policies and recording practices can result in discrepancies in data between states and territories. This is explored in further detail in chapter 3 using Crime Victimisation Survey data and Recorded Crime - Victims administrative data as an example.

Survey data

Surveys of individuals in the community provide a way of asking people directly about their experiences of crime. Such surveys are designed specifically for statistical purposes. In the field of crime and justice, often one of the primary reasons for conducting a survey is that many victims of crime do not report their experiences to police, and so are not counted in administrative data. Victimisation surveys are a way to tap the ‘dark figure’ of crime (Coleman & Moynihan, 1996). The ‘dark figure’ refers to the volume of incidents that are not officially recorded. Data obtained from surveys may provide a more accurate representation of the ‘true’ figure of crime. 

Surveys use a sample of the population to represent the experiences and perceptions of the entire population. The disadvantage of using this methodology is the sampling error that can be associated with the estimates produced, which refers to the error caused by using a sample of the population rather than surveying the whole population (for further discussion of sampling error, please refer to the technical note). Surveys are also expensive and time-consuming to design and undertake. Crime Victimisation topics are included in four surveys produced by the ABS.

Crime Victimisation Survey

The Crime Victimisation Survey is an annual survey conducted using the ABS Multipurpose Household Survey (MPHS). The survey collects data about victims for a selected range of personal and household offences including assault, threatened assault, sexual assault, robbery, break-in, attempted break-in, motor vehicle theft, theft from a motor vehicle and malicious property damage. The survey also provides information about the characteristics of victims, the characteristics of their most recent incident and whether the incidents were reported to police.

Key findings from the Crime Victimisation Survey are presented in Crime Victimisation, Australia (cat. no. 4530.0).

Personal Safety Survey

The Personal Safety Survey (PSS) measures the nature and extent of violence against men and women and the effects of this violence. It also provides information on abuse, harassment and on people's feelings of safety within the home and in the community. The survey was conducted as a face-to-face private interview and the survey design used special procedures to achieve the targeted numbers of females and males. Data are classified by demographic characteristics.

Key findings from the PSS are presented in Personal Safety Survey, Australia, 2005, (Reissue) (cat. no. 4906.0).

General Social Survey

The ABS General Social Survey (GSS) is a multi-topic survey conducted for the first time in 2002 and repeated every four years. The survey brings together a wide range of information to enable it to be linked across areas of social concern. The focus is on the relationship between characteristics from different areas, rather than in depth information about a particular field. The GSS is conducted by interview with one respondent aged 18 years and over, randomly selected per household. The respondent is asked a series of questions by an ABS interviewer for each topic of social concern included in the survey. For the crime and safety topic the questions cover experiences of assault, break and enter and feelings of safety.

Key findings from the General Social Survey are presented in General Social Survey: Summary Results, Australia 2006 (cat. no. 4159.0). Results from the latest GSS are expected to be released at the end of September 2011.

National Aboriginal and Torres Strait Islander Social Survey

The National Aboriginal and Torres Strait Islander Social Survey (NATSISS) was conducted from August 2008 to April 2009 with a sample of Aboriginal and Torres Strait Islander people living in private dwellings across Australia. The NATSISS is a multidimensional social survey that provides broad information across key areas of social concern for Indigenous Australians, nationally, by state and territory and remoteness area. Key topics within the law and justice domain include whether the respondent was a victim of physical or threatened violence within the past 12 months, whether the respondent had contact with the police since the age of 15, and the use of legal services since the age of 15.

Key findings from the NATSISS are presented in National Aboriginal and Torres Strait Islander Social Survey, 2008 (cat. no. 4714.0).

Comparisons across survey data

Each of the surveys described collects data about different aspects of crime victimisation, however there are some concepts and data items that are common across all of the surveys. The data produced from these items differ across the surveys due to differences in the survey methodology employed to collect information. Each survey is unique in the following aspects of survey design and operations:

  • Sample design and selection – Decisions on the appropriate sample size, distribution and method of selection are dependent on a number of considerations. These include the aims and content of the survey, the level of disaggregation and accuracy at which the survey estimates are required, and the costs and operational constraints of conducting the survey.
  • Scope and Coverage – Depending on the survey requirements and constraints, the scope and coverage of the surveys differ. For example, the Crime Victimisation Survey excludes people living in very remote areas, whereas very remote areas are included in the scope of the NATSISS.
  • Questionnaire format – Different results can be expected if the questionnaire format differs across the survey instruments. The GSS for example, covers a range of topics within which the crime and justice questions are asked around the middle of the survey. The PSS on the other hand is entirely devoted to questions about the safety of the individual. This may produce a context effect for respondents, which means that the order of the questions could impact on the responses given. This then may impact on the results of the survey.
  • Survey procedures – Survey procedures relate to the mode of the data collection and any special procedures required. The Crime Victimisation Survey is generally conducted using a short telephone interview whereas the GSS and the PSS use longer face-to-face interviews. Both methods have advantages and disadvantages that can impact on the survey results. For a full discussion of the impact of different survey procedures, please refer to Information Paper: Measuring Crime Victimisation, Australia: The impact of different collection methodologies, 2002 (cat. no. 4522.0.55.001).
  • Response rate – Response rates give an indication of the influence of non-response bias on the data collected in the survey. These vary across the surveys; for example, the 2009-10 Crime Victimisation Survey had a response rate of 87% whereas the response rate for the PSS 2005 was lower at 77%. As such, the influence of non-response bias on the survey data differs between the surveys.


Due to the factors described in relation to survey design and operations, each survey data set should be considered a unique stand-alone dataset and data items, even when appearing to measure similar concepts, should not be compared across the different survey data sources.

Comparisons between crime administrative data and crime survey data

As discussed at the beginning of this chapter, there are key differences between administrative data and survey data. There are also specific additional factors unique to crime data that further differentiate administrative and survey data.

Reported and unreported crime

The purpose of the Recorded Crime - Victims collection is to present national statistics relating to victimisation incidents recorded by police for a selected range of offences. To enable a criminal incident to be recorded, the victim, witness or concerned citizen has to acknowledge a crime has occurred and make the decision to notify police, and then police need to enter this data into the crime recording system. To the extent that these prerequisites are not met, the statistics in this collection will not provide counts of the total number of crime victims in Australia.

Crime victimisation surveys, such as the ABS Crime Victimisation Survey, are designed to collect experiences of individuals and households of selected crimes regardless of whether or not they reported their victimisation to police, to estimate the prevalence of crime victimisation across the community. ABS crime victimisation surveys require the victim to have acknowledged that an incident has occurred, and to be willing to report this incident to the ABS interviewer. In general, this means that the victimisation rates reported in the crime victimisation surveys are higher than the victimisation rates reported in the police recorded data; the surveys are able to capture crime that goes unreported to police. It is important to note that there will always be a hidden unknown proportion of crime that goes unreported in both the official police statistics and the survey data.

Definitions of crime

While the ABS crime victimisation surveys include definitions for the selected personal and household crimes included in the interview, the surveys are reliant upon the respondents recognising the behaviours that constituted the criminal incident and reporting this to interviewers. For example, the Crime Victimisation survey asks respondents ‘Since June last year, did anyone, including people you know well, use physical force or violence against you’. This is a broad behaviour-based question that is designed to elicit response without the constraint of defining the crime itself in legal terms. Police recorded administrative data is collected as part of the business process of the police agencies across Australia which is governed by legislation and the criminal code. It is possible that a respondent may report some incident of violence in the survey and report this to police, however it may not constitute a crime in accordance with the criminal code and as such would not be included in the police statistics. 

Conclusion

Measuring crime victimisation accurately within the community is a challenging task. Throughout this chapter the issues associated with data collection were briefly discussed and it was acknowledged that no single data source is able to comprehensively cover all facets of crime victimisation in the community. Instead, data from both administrative and survey data sources are useful to provide information about particular aspects of victimisation. The ABS maintains two administrative data sources in relation to crime victimisation and four surveys containing crime victimisation information. Each data source produces different results due to the different areas of focus and methodologies employed in collecting the data.

The next chapter explores the differences between the data from different sources in greater detail by using a working example that compares the Crime Victimisation Survey data with police recorded statistics as collected for the Recorded Crime – Victims collection.

Chapter 3 - Analysis of Crime Victimisation Survey data and police recorded administrative data

Introduction

The previous chapter examined the broad differences between administrative data and survey data with particular reference to the specific issues in measuring crime victimisation. This chapter continues to examine the differences between data sources using a working example of offence data from Recorded Crime – Victims, Australia(cat. no. 4510.0) and Crime Victimisation, Australia (cat. no. 4530.0). 

This chapter of the Guide aims to answer the questions: What kinds of differences exist between and within different crime victimisation data sources that users need to be aware of when using the data? How can the quality of one source be examined using another source? What do users of crime victimisation data need to keep in mind when looking to bring multiple sources together for analysis or comparison?

In order to assess the degree of comparability between different sources of data it is important to have a clear understanding of the scope, coverage and methodology used for data collection. Where it is not possible to make direct, meaningful comparisons between sources, the trends that arise in the data can still be useful in identifying quality issues and patterns over time. 

To illustrate the process of assessing multiple sources and to highlight some of the different considerations to be taken into account when determining comparability, this chapter will look at an example comparing two different forms of ABS crime victimisation data. The first dataset is created from a sample survey – the Crime Victimisation Survey – and the second dataset is the Recorded Crime – Victims, Australia statistical collection, which comprises recorded crime data sourced directly from policing agencies in each state and territory in Australia. These datasets contain similar concepts: the survey asks respondents about crimes that police have been told about, while the data collected from police represents crimes they have recorded on their administrative systems. These sources can produce quite different statistics, however, and are not easily reconciled. Understanding the different scope and coverage of the sources is imperative to understanding why the resultant statistics can differ.

Know your dataset - understanding general scope and coverage differences

This illustration explores the differences between the Crime Victimisation Survey and the Recorded Crime – Victims police administrative data collectionThere are a number of fundamental differences between the two sources: the way the data is collected, whom it is collected from, the offences that are in scope, the population that is in scope, the geographical regions that are covered and the reference period within which the data is collected.

Purpose of data collection

While these statistical collections contain data about closely related concepts (people who have their crime victimisation recorded by police and people who are surveyed by the ABS and tell the interviewer that they have been a victim of a crime and that police were told), in practice they are quite different. The first important point to note is the purpose of the data collection. The administrative data about victims of selected criminal offences that is supplied by state and territory police agencies to the ABS is collected as part of the business of the policing agency – not purely for statistical purposes. As such, the data collection is shaped by the different business practices of each policing agency and the environment and context in which they operate. 

The crime victimisation survey run by the ABS, however, is a data collection exercise which exists only for the collection of statistical data and involves the ABS directly seeking responses from a sample of Australian households about the experience of a range of criminal offences, and opinions about other crime and justice-related topics. As such, the survey data collection does not become influenced by differences in business practice and organisational context across states and territories, but can be influenced by sampling error and the impact of different survey collection methodologies and question wording. Thus, from the beginning of the exercise, it is quite clear that there are likely to be some differences between the data gathered from each of these sources.

Offence scope

The collections also cover different offence types. The Recorded Crime – Victims collection only includes selected offences from the range under the remit of policing agencies. The crime victimisation survey similarly focuses on personal and household crimes that are of policy interest and community impact, and where respondents are likely to be able to report their victimisation to an interviewer. For the purposes of this illustration, three personal offence types that are included in both collections are included in this analysis: assault, sexual assault and robbery; as well as two household offences: break-in and motor vehicle theft. Other offence types collected in the Crime Victimisation Survey, such as malicious property damage and other theft do not align with the crime types included in the Recorded Crime - Victims collection and therefore are not included in this analysis.

Population scope and geographical coverage

The survey data and data collected from police differ in population scope and coverage. The police data covers people and organisations who are recorded as victims of crime in almost all areas in Australia (with the exclusion of some spaces under the jurisdiction of the Australian Federal Police, such as major airports and the Cocos (Keeling) Islands) whereas the ABS survey sample does not reach all Australians in all areas. The Crime Victimisation Survey is only asked of Australians selected for the survey who are over 15 years of age (with proxy interviews by parents or guardians possible for respondents under the age of 18) and over 18 years of age for the sexual assault questions. The survey also excludes people who live in areas of Australia that are considered very remote. The exclusion of some areas of Australia from the sample survey is due to the degree of difficulty in accessing some very remote areas and the prohibitive costs of sending interviewers into difficult terrain and areas that are a long way from major centres. For a full listing of the scope and coverage of each collection please refer to the Methodology for Recorded Crime - Victims, Australia (cat. no. 4510.0) and Crime Victimisation, Australia (cat. no. 4530.0).

As a result, if we are to look at comparing the survey and administrative datasets, we need to try and align the coverage of the administrative data with the more restricted survey data. In the example discussed throughout this chapter, we have made the following amendments to the datasets:

  • Removal of Recorded Crime – Victims data for persons under the age of 15 years for all general offences, and persons under the age of 18 years for sexual assault.
  • Removal of Recorded Crime – Victims data for persons living in very remote areas of the Northern Territory. The Crime Victimisation Survey does not include very remote areas within scope of the survey. For most jurisdictions the exclusion of very remote areas will not affect comparability, given they account for only approximately 1% of the population. For NT, however, this equates to approximately 23% of the population and therefore adjustments have been made to the administrative data to align with the scope of the crime victimisation survey data.
  • Removal of Recorded Crime – Victims data about organisations; data is presented for households and persons only.
  • Removal of unreported crime incidents from the Crime Victimisation Survey - only victims who say the most recent crime incident was reported to police are included to align more accurately with the police recorded victims data.
     

Reference period

The Crime Victimisation Survey data is collected on a financial year basis (for example July 2008 to June 2009), while the Recorded Crime – Victims data is collected on a calendar year basis (for example January 2008 to December 2008). Questions within the Crime Victimisation Survey ask respondents to refer to the 12 month period prior to participating in the survey. For example, for survey interviews conducted in September 2009, the respondent is asked to report any incidences of physical force or violence they have experienced since September 2008. This means that the potential span of data from the survey ranges from July 2007 (the earliest offence date for respondents who were interviewed in July 2008) to June 2009. The centre point to the survey recall period is June 2008. June 2008 is also the centre point of the Recorded Crime – Victims data. As such, the 2008-09 data from the survey and the 2008 Recorded Crime – Victims data are considered a suitable approximation for comparison. Similarly the 2009-10 Crime Victimisation Survey data and the 2009 Recorded Crime – Victims data are considered a suitable approximation for comparison.

For a complete outline of the methodology used for this analysis, please refer to the technical note.

Comparing survey estimates with administrative data

Data recorded by police is essentially a census where all counts should be supplied as part of the data collection. The survey data is created from responses given by a sample of the Australian population that is then weighted. Weighting is a process that is undertaken in order to produce estimates of the prevalence we would find for these offences if the entire Australian population had been included in the survey. When using survey data for any analysis, the reliability of the estimates must be considered. Since the estimates in the Crime Victimisation Survey are based on information obtained from a sample of persons, they are subject to sampling variability. Sampling variability means that the estimates may differ from those that would have been produced if all persons were included in the survey.

The standard error (SE) is a measure which indicates the extent to which an estimate might have varied because only a sample was used. Using this measure, the likely range within which the value that would have been produced if all persons had been included in the survey can be calculated. There are about 19 chances in 20 (or a 95% chance) that the difference between the survey estimate and the true value is less than two standard errors based on the Crime Victimisation Survey. We will be referring to this range as the 95% confidence interval. Standard errors for values presented in graphs are displayed below each graph in a table.

Diagram showing the 95% and 68% confidence intervals for a published estimate.
The published estimate is 75,000. There are two chances in three that the true value is in the range of 63,900 to 86,100, and 19 chances in 20 that the true value is in the range of 52,800 to 97,200.

When comparing the survey estimates and the administrative data, it is this range above and below the survey estimate that will be considered in the analysis rather than the estimate itself. Where the recorded crime data falls within the range of the estimate, there is a degree of consistency between the data sources. That is, there is insufficient evidence to conclude that there is any difference between the recorded crime value and the population value underpinning the survey estimate (i.e. the values are not statistically significantly different). For example, there are 19 chances in 20 (or a 95% chance) that the true value for the number of persons reporting physical assault in NSW was between 52,800 and 97,200 in 2008-09. The recorded crime figure for total assaults is 72,400, which falls within the confidence interval for the survey estimate, therefore in this case, the administrative data value and the survey estimate are not statistically significantly different.

Expected differences between survey estimates and administrative data

It is generally expected that the estimated number of victims who stated they reported their victimisation to police in the survey will be higher than the number of victims counted in the administrative collection. The survey uses a broad behavioural definition for offences rather than a strict legal definition that is adhered to within the justice system. For example, the definition of physical assault in the Crime Victimisation Survey is an incident where anyone used physical force or violence against the respondent, including being pushed, grabbed, shoved, slapped, hit with an open hand or fist, kicked or bitten. The police administrative data is subject to legislative constraints and business process rules. This may mean that while a respondent in the survey considered themselves to be a victim of assault and reported that incident to police, that incident will not necessarily be recorded by the police as it may not meet the legal requirements of an incident of assault.

Illustration of differences in crime victimisation data by offence

So far, this illustration has focused on the broad differences that can be seen in the characteristics of datasets across scope, coverage and source. These differences can affect certain offences in different ways due to the specific nature of the offence, the way that victims respond to the event, and sensitivities around reporting to police and other authorities (such as official surveys). By examining each of the selected offences in turn, it is possible to gain a better understanding of the visible differences that can result in statistics as a result of these issues.

Assault

Assault statistics from the RCVS collection and estimates from the survey data demonstrate the issues encountered when there is variation in the definitions between data sources and recording practices within data sources. For the survey, the data that is presented relate only to physical assaults that respondents state have been reported to police. The recorded crime data from police records relate to all assaults (attempted and completed). For the detail around these different scopes, please refer to the technical note. This offence demonstrates the impact of different recording and business practices across jurisdictions.

The graphs below compare the estimated number of victims of physical assaults who reported to police from the 2008-09 and 2009-10 Crime Victimisation Survey with the number of victims of total assault recorded by police in the Recorded Crime – Victims collection for 2008 and 2009 respectively. 

Download
  1. Includes only respondents who stated the most recent incident of assault was reported to police.
  2. Data has been adjusted to align with the Crime Victimisation Survey data, refer to technical note for further details.
  3. Data excludes counts determined as 'no crime'. For more information refer to technical note.
  4. Refers to mainly urban areas. For more information refer to technical note.

Sources: Crime Victimisation, Australia 2008-09 (cat. no. 4530.0) and Recorded Crime – Victims, Australia 2008 (cat. no. 4510.0).


The survey estimates have been plotted to include bars to show the range of the 95% confidence interval and the police data has been plotted as direct counts. Despite differences in methodology and content between the data sources, for NSW, SA, WA, NT and the ACT the number of victims of assault as collected in Recorded Crime – Victims falls within less than two standard errors of the survey estimate for the number of victims of physical assault. In this sense, the assault statistics sourced from these two collections can be said to be consistent. 

For Victoria, Queensland, and to a lesser extent, Tasmania, the recorded crime data for total assaults is statistically significantly lower than the survey reported estimates for physical assault.

Download
  1. Includes only respondents who stated the most recent incident of assault was reported to police.
  2. Data has been adjusted to align with the Crime Victimisation Survey data, refer to technical note for further details.
  3. Refers to mainly urban areas. For more information refer to technical note.

Sources: Crime Victimisation, Australia 2009-10 (cat. no. 4530.0) and Recorded Crime – Victims, Australia 2009 (cat. no. 4510.0).


For the 2009 reference period, the Recorded Crime data for Victoria, Queensland and Tasmania still fall below the range of the survey estimate, with the addition of Western Australia.

Why are the administrative data and survey data less consistent for some jurisdictions than others?

As previously discussed, the data that is collected by a police agency for operational purposes is a product of local business rules, context and legislation. In order to try and standardise statistical data across the states and territories to enable the compilation of national statistics, each state and territory police agency worked with the ABS to develop a National Crime Recording Standard (NCRS). Agreed NCRS manuals were distributed to jurisdictions in 2007. 

The NCRS was developed to address the lack of uniformity in initial police recording processes. The NCRS guides the recording and counting of criminal incidents for statistical purposes and enables consistency in recording. While the application of the rules and requirements of the NCRS generally enable the recording of crime in a comparable manner across the jurisdictions, there is some variability in the interpretation and implementation of the rules, in particular the rule which guides what is recorded on the police systems when an incident is reported to police.

Here is the relevant rule in full:

An incident will be recorded as one or more offences if prima facie (on the face of it) and on the balance of probability (more probable than not):

  • The circumstances as reported or detected amount to a crime defined by law and fall within the jurisdiction of the police agency; and
  • There isn't credible evidence to the contrary.
     

This rule provides a common basis for recording an incident with one or more offences according to the judgement of the police officer (as distinct from evidentiary or prosecutorial reasons).

Differences in interpretation and implementation of the rule for assault by jurisdiction

JurisdictionsInterpretation for assault incidentsEffect on assault data
New South Wales, South Australia, Western Australia, Northern Territory and the Australian Capital TerritoryWhen a victim reports an incident to police it is taken on ‘face value’ and recorded as an incident on their crime recording system. An investigation will follow to determine whether a crime has been committed. Note that there are different degrees to which this approach is applied across these jurisdictions.Is largely consistent with findings of the Crime Victimisation Survey
VictoriaSome element of an investigation will be undertaken before deciding whether to record an incident on their crime recording system. A record of the incident may be taken on other systems, however the incident will not be recorded on the police crime recording system until it is determined that a crime has been committed.Produces assault statistics that are lower than those produced by the Crime Victimisation Survey
QueenslandWhen an incident is reported to police, it is not taken on ‘face value’ and recorded on the Queensland Police Records and Information Management Exchange (QPRIME).

While Queensland police make a record of all initial assault complaints, they do not formally record matters that are unsubstantiated.
Produces assault statistics that are lower than those produced by the Crime Victimisation Survey
TasmaniaFor most incidents, when a victim reports an incident to police it is taken on ‘face value’ and recorded as an incident on their crime recording system. For a small number of cases some initial investigation is undertaken before deciding whether to record an incident on their crime recording system.May produce assault statistics that are lower than those produced by the Crime Victimisation Survey


The difference in the interpretation of this rule is evident in the results of the comparisons between the Crime Victimisation Survey data and the Recorded Crime – Victims data for assaults. For the jurisdictions that interpret the rule as requiring recording based on the report of the victim, the recorded crime data falls within the 95% confidence interval of the survey estimate. For the remaining jurisdictions that require a determination prior to being recorded, the recorded crime data falls outside the 95% confidence interval of the survey estimate. 

There are also more specific issues that can affect a jurisdiction’s data, such as specific legislative differences and administrative practices. Results for the four states where there were differences between the survey results and the administrative data (Victoria, Queensland, Western Australia (in 2009-10 only) and Tasmania) are explored in more detail in the following.

Victoria

There are two major policy documents that provide direction to Victoria police in the recording of information: one relates to general crime, and the other relates specifically to assault. Policy changes in accordance with the NCRS have been made to the general crime documents, but the recording of assaults continues to be evidentiary based. The assault incidents that are reported to police are initially entered into a patrol duty return, however investigation will be conducted before these are entered into the crime recording system.

For family and domestic violence incidents that involve assault, police will complete a Family Violence Report indicating that assault has occurred but these are not recorded on the crime recording system in all instances. 

Queensland

One reason for the differences between the recorded crime data sourced from Queensland police and the survey estimates is the more evidentiary approach taken to recording assaults in Queensland, ie the initial report is not taken on face value, in comparison to other jurisdictions, such as New South Wales, South Australia, Western Australia, Northern Territory and Australian Capital Territory. However, there is also a secondary contributor to the difference between the data sources, and this is the application of Queensland family and domestic violence legislation. 

All first instances of domestic violence must be investigated, and action can be taken under the Domestic and Family Violence Protection Act 1989 regarding a domestic incident. If there is evidence of a criminal offence, these matters will also be investigated and appropriate action taken where there is sufficient evidence. If the criminal offence involves an assault, proceedings will only be commenced with the consent of the victim.

The Criminal Code Act 1899 deals with all criminal assault matters. Where a domestic violence incident has occurred which involves an assault, but the victim does not consent to proceeding with the assault charge, then the assault matter will not be recorded on the Queensland Police Records and Information Management Exchange (QPRIME).

In consideration of the legislation described, if a Queensland respondent in the crime victimisation survey stated they were physically assaulted and reported the most recent incident to police, but in reality did not consent for police to proceed with the assault charge, the incident would have been counted in the survey, but would not be included in the police recorded crime data. In other jurisdictions where family and domestic violence incidents are recorded even if the victim does not want to proceed, the incident would be included in the police recorded crime data.

Queensland data analysis - 2009-10

The survey data for 2009-10 showed a significant increase in the number of victims reporting physical assaults to police in comparison to 2008-09, while the police recorded victims data remained fairly steady. Given that the survey is based on a set of responses from a sample of the Australian population, each estimate is associated with a level of error, and variation can occur between reference periods. Rather than focussing on a single estimate in isolation, the estimates are more useful for indicating a trend over time. Currently there are only two points of measurement for the assault estimate from the Crime Victimisation Survey, so it is difficult to judge whether the 2009-10 estimate for Queensland is due to sampling error or reflects a genuine increase in the number of reported victims of assault. Further results from the survey over the coming years will allow greater analysis of the data trends.

Western Australia

Western Australian police will accept the report of the victim on face value in accordance with their interpretation of the NCRS. Like other jurisdictions that adopt a similar approach, Western Australian recorded crime data for assaults in 2008-09 was lower than the survey estimate, but within the 95% confidence interval of the survey estimate. In 2009-10, however, the number of victims of assault from the recorded crime data is statistically significantly lower than the survey estimate.

Tasmania

Tasmania police operate two separate systems for crime victim recording: the Computer-Aided Dispatch System (CAD) and the Offence Reporting System. All initial reports are recorded through the police communications area in the CAD. The Offence Reporting System records crimes or offences where on face value an offence appears to have been committed. All assaults are reported on the offence reporting system unless there is evidence to suggest that no offence was committed.

Crime statistics as disseminated in Recorded Crime – Victims are sourced from the Offence Reporting System. 

The results of the 2009-10 analysis produced a closer match between the Tasmanian survey results and recorded crime data than 2008-09, however the recorded crime figure was again statistically significantly lower than the survey estimate. The counts for Tasmania are small and as such are subject to relatively more variation than the larger states. 

Given these differences, which comparisons can be made across jurisdictions for the assault data gathered from police statistics?

This example shows the difficulties in obtaining consistent and comparable assault data across jurisdictions (based on police data) due to their different legislative frameworks, business practices, crime recording systems and interpretation of the national crime recording standard. It is therefore recommended that police recorded crime data for assault not be compared across jurisdictions for these reasons. In order to make comparisons between jurisdictions, it is recommended that Crime Victimisation Survey data be used, as this data is not subject to differences in practices or definitions across jurisdictions, and is hence comparable across Australia.

Do these issues occur particularly with assault?

The lack of comparability between some jurisdictions for assault data is specific to this offence, due to a range of reasons:

  • Different legislative definitions and requirements across jurisdictions relating to assault;
  • The ambiguity that can arise in determining what has occurred in an alleged assault incident;
  • Difficulty in determining the role different parties have played in an assault incident; and
  • Protocols that exist for reporting on family and domestic violence and other specific types of assaults.
     

All of these factors can result in different counts for assault depending on when in the investigative process (before or during) a decision to record is made. 

Sexual assault

Due to the sensitive nature of sexual assault, it is often a crime that goes unreported to police authorities, services, friends and family. According to the Crime Victimisation Survey, in 2009-10, 36.6% of the most recent incidents of sexual assault were reported to police. The reporting rate for sexual assault is relatively low when compared with other personal offences: the estimated national reporting rate for physical assault in 2009-10 was 50.5% and for robbery the estimated national reporting rate was 60.7%. It follows then that survey respondents may also be reluctant to answer questions about sexual assault via a telephone survey. As such, the questions about sexual assault are asked only of persons aged 18 years and over. Corresponding data from the Recorded Crime – Victims collection has been limited to 18 years and above for the purposes of this analysis.

Sexual assault offences are often reported to the police at a time well after the incident had occurred. That is, the sexual assault victims recorded in the police recorded data may have been reporting in relation to an incident which occurred many years ago, whereas the survey questions limit responses to victimisation events that occurred within 12 months prior to the survey interview. 

For both 2008 and 2009, all recorded crime sexual assault figures were within the 95% confidence interval for the survey estimate, although the confidence intervals are so large as to render the survey estimates too imprecise for comparative purposes.

The low prevalence of sexual assault in the community in comparison with some other surveyed offences should be considered when interpreting the results of this comparison. Low prevalence offences are associated with higher levels of survey sampling error. This higher error makes it more difficult to assess the consistency between the sources to a high degree of precision. It also emphasises the fact that the figures produced from the survey are sample-based estimates only and that the reliability of the data needs to be taken into account when using the data. The Personal Safety Survey delivers more detailed data for this offence type as a result of a more in-depth and private interview methodology and should be referred to if more data about this offence type is required.

Download
  1. Includes only respondents who stated the most recent incident of sexual assault was reported to police.
  2. Data has been adjusted to align with the Crime Victimisation Survey data, refer to technical note for more details.
  3. Data excludes counts determined as 'no crime' 
  4. Refers to mainly urban areas. For more information refer to technical note.
  5. Survey data not available for publication

Sources: Crime Victimisation, Australia 2008-09 (cat. no. 4530.0) and Recorded Crime – Victims, Australia 2008 (cat. no. 4510.0).

Download
  1. Includes only respondents who stated the most recent incident of sexual assault was reported to police.
  2. Data has been adjusted to align with the Crime Victimisation Survey data, refer to technical note for further details.
  3. Survey data is not available for publication.
  4. Refers to mainly urban areas. For more information refer to technical note.

Sources: Crime Victimisation, Australia 2009-10 (cat. no. 4530.0) and Recorded Crime – Victims, Australia 2009 (cat. no. 4510.0).

Sensitivity around reporting for sexual assault

While there is a high rate of victims of sexual assault not reporting the offence to the Police, similar sensitivities around reporting (trauma, embarrassment, shame, fear of reprisal or other consequences for an offender) also can influence the readiness of a victim to report an incident in a crime victimisation survey. The methodology employed for the crime victimisation survey is a telephone interview, and while the ABS maintains the privacy and confidentiality of respondents, it is possible that a respondent may not feel comfortable to report an offence in this situation or be able to complete the interview without others listening to the call. Different survey methodologies can have a large impact upon the results generated for sexual assault victimisation and other very personal offences, and have been discussed in several ABS publications. For more information, please see Information Paper: Measuring Crime Victimisation, Australia: The impact of different collection methodologies, 2002 (cat no 4522.0.55.001).

Robbery

Robbery is both a personal and acquisitive offence, which can cause some challenges in definitions and understanding differences in scope across statistical collections. Generally in 2008, for most jurisdictions, the recorded crime data for victims of robbery fell within the 95% confidence interval of the survey estimate of victims who reported a robbery to police. Western Australian and Tasmanian data for robbery was slightly below the survey estimate. 

Download
  1. Includes only respondents who stated the most recent incident of robbery was reported to police.
  2. Data has been adjusted to align with the Crime Victimisation Survey data, refer to technical note for further details.
  3. Data excludes counts determined as 'no crime'
  4. Refers to mainly urban areas. For more information refer to technical note.

Sources: Crime Victimisation, Australia 2008-09 (cat. no. 4530.0) and Recorded Crime – Victims, Australia 2008 (cat. no. 4510.0).

Download
  1. Includes only respondents who stated the most recent incident of robbery was reported to police.
  2. Data has been adjusted to align with the Crime Victimisation Survey data, refer to technical note for further details.
  3. Refers to mainly urban areas. For more information refer to technical note.
  4. Survey data not available for publication 

Sources: Crime Victimisation, Australia 2009-10 (cat. no. 4530.0) and Recorded Crime – Victims, Australia 2009 (cat. no. 4510.0).


Reporting rates from the Crime Victimisation Survey for the most recent incident of robbery increased significantly at the national level between 2008-09 and 2009-10, from 39% to 60%. This was driven by particular increases in reporting in Western Australia and Queensland. 

Why are these figures inconsistent between years?

Robbery, like sexual assault, is an offence which tends to have a lower prevalence within the community than other offences, and therefore is subject to greater survey error and variability. As a result, the estimates can be more volatile and inconsistencies can emerge over time. Given that the survey is based on a set of responses from a sample of the Australian population, each estimate is associated with a level of error, and variation can occur between reference periods. Rather than focussing on a single estimate in isolation, the estimates are more useful for indicating a trend over time. Currently there are only two points of measurement for the robbery estimate from the Crime Victimisation Survey. Further results from the survey over the coming years will allow greater analysis of the data trends.

Break-in

In the crime victimisation survey, break-in covers instances where there has been a break-in to a person’s home (including garages, sheds and caravans). As police recorded crime data is collected on a wider scope (including organisations, retail premises, etc.), the following data has been adjusted so that only residential properties are included. 

For both 2008 and 2009, almost all recorded crime data for break-in falls below the 95% confidence interval of the survey estimate for break-in, with the exception of New South Wales and Tasmania in 2008 and New South Wales and the Australian Capital Territory in 2009.

Download
  1. Includes only respondents who stated the most recent incident of break in was reported to police.
  2. Data has been adjusted to align with the Crime Victimisation Survey data, refer to technical note for further details.
  3. Data excludes counts determined as 'no crime' 
  4. Refers to mainly urban areas. For more information refer to technical note.

Sources: Crime Victimisation, Australia 2008-09 (cat. no. 4530.0) and Recorded Crime – Victims, Australia 2008 (cat. no. 4510.0).

Download
  1. Includes only respondents who stated the most recent incident of break in was reported to police.
  2. Data has been adjusted to align with the Crime Victimisation Survey data, refer to technical note for further details.
  3. Refers to mainly urban areas. For more information refer to technical note.

Sources: Crime Victimisation, Australia 2009-10 (cat. no. 4530.0) and Recorded Crime – Victims, Australia 2009 (cat. no. 4510.0).

Difficulties in defining break-in

Break-ins can be difficult to define in a way respondents can easily understand in a telephone survey. Cognitive testing of the survey questions has shown that survey respondents are often eager to report incidents of property damage, theft and general household related crime. Break-in is the first household crime module respondents encounter in the survey and as such, respondents often want to report incidents of property damage and other theft (which does not involve a break-in) within the break-in module. The ABS has modified this module for the 2011-12 survey onwards to provide greater clarity for respondents and filter out other related but non break-in incidents that presently may be appearing in the survey-based break-in statistics.

Motor vehicle theft

Motor vehicle theft is relatively simple to define in comparison to some of the other crime types included in the Crime Victimisation Survey. In addition, motor vehicle theft has a high reporting rate; 90% of victims reported their most recent incident of motor vehicle theft to police in 2009-10 nationally. 

With the exception of Queensland in 2008 and Tasmania and Queensland in 2009, jurisdictions’ recorded crime data was within the 95% confidence interval of the survey estimate for motor vehicle theft. The difference between the survey data and the recorded crime data for Tasmania and Queensland is very small. It is worth noting that all respondents in Queensland who said they were a victim of motor vehicle theft also said they reported the theft to police, which means that for motor vehicle theft, Queensland had an estimated reporting rate of 100%. As with all the results from the survey, the reporting rate is subject to sampling error. This may have contributed to the discrepancy between the survey estimate and the recorded crime figure. The true value of the reporting rate if all persons responded may be less than 100%, which would have the effect of reducing the number of victims who reported to police in the survey results.

Download
  1. Includes only respondents who stated the most recent incident of motor vehicle theft was reported to police.
  2. Data has been adjusted to align with the Crime Victimisation Survey data, refer to technical note for further details.
  3. Data excludes counts determined as 'no crime'
  4. Refers to mainly urban areas. For more information refer to technical note. 

Sources: Crime Victimisation, Australia 2008-09 (cat. no. 4530.0) and Recorded Crime – Victims, Australia 2008 (cat. no. 4510.0).

Download
  1. Includes only respondents who stated the most recent incident of motor vehicle theft was reported to police.
  2. Data has been adjusted to align with the Crime Victimisation Survey data, refer to technical note for further details.
  3. Refers to mainly urban areas. For more information refer to technical note.
  4. Survey data not available for publication

Sources: Crime Victimisation, Australia 2009-10 (cat. no. 4530.0) and Recorded Crime – Victims, Australia 2009 (cat. no. 4510.0).

Why is the data so consistent between the sources for motor vehicle theft?

As motor vehicle theft is an offence that is readily understood and not subject to much ambiguity in terms of legal definitions, motor vehicle theft tends to be very robust across both states and territories for police recorded data and for the crime victimisation surveys. The other important point to note is the very high reporting rate, which is generally assumed to be a product of the incentive for victims in claiming insurance for their stolen car. Insurance agencies generally require a police report in order to process such a claim. 

Conclusion - chapter 3

The differences between the police recorded crime administrative data and the Crime Victimisation Survey data vary depending on the offence type. This is in part due to the nature of the offences themselves. Sexual assault for example has a low prevalence rate within the community and is a sensitive and very personal offence which means it often goes unreported to police or other authorities, whereas motor vehicle theft occurs much more frequently and is almost always reported to police in order to fulfil insurance requirements. Other effects differ between offence types due to the degrees of sampling error associated with the survey estimates, differences in recording practices, and difficulties in defining the offence itself.

The demonstration of the differences between the data sources shows the importance of understanding the purpose, coverage, scope and definitions of a particular source before making a decision to use the data.

Chapter 4 - Guide to using each data source

Introduction

Both the victimisation survey data and the administrative data contribute to informing users about the nature and extent of crime victimisation. Neither administrative statistics nor crime victimisation surveys alone can provide comprehensive information about crime, rather the two types of data sources can be used to test alternative hypotheses related to criminal activity (Statistics Canada, 1997). For example, data from victimisation surveys can be used to examine the extent to which particular offence types go unreported to police, which is not possible using police recorded crime data. However, the police recorded crime data is useful in understanding policing activities within each of the states and territories.

The purpose of this chapter is to provide a guide as to which data source is best suited for particular research purposes. All data sources have strengths and limitations, however, and these also need to be considered to determine whether a source is fit for purpose.

Summary information for each ABS crime data source

The following table provides an overview of the purpose and frequency of data collection for each crime data source, as well as details of past releases, the geographic level for which data is available, a summary of the crime related data items, and examples of research questions that can be answered using the different data sources.

PublicationPurpose of data collectionFrequency of data collectionPast releasesLevel of data availableCrime Data item SummaryExample Research Questions
Recorded Crime – Victims, Australia (cat. no. 4510.0)Presents statistics about victims of a selected range of personal and household offences which have been recorded by police in each state and territory.Annual (calendar year basis)1993 onwardsNational and state and territory data for all selected offences, with the exception of assault data for which state and territory data only is available.Includes data for victim characteristics, for example, age, sex, Indigenous status (selected states only), nature of the incident (weapon use and location) and outcome of police investigations.

Note that child victims (aged between 10 and 17) are included in this dataset.
How many victims of manslaughter were recorded by police in 2010?

What proportion of sexual assault victims, recorded by police during 2008, were under the age of 18?

Of the incidents of physical assault that were recorded by police, what proportion of these occurred in the home?
Causes of Death, Australia
(cat. no. 3303.0)
Presents statistics on deaths and mortality in Australia.Annual (calendar year basis)1993 onwardsNational, state and territory, and sub-state regions.Includes data about deaths through assaults and characteristics of the deceased such as place of usual residence, age at death, sex, Indigenous status and country of birth.Are the number of deaths through assaults in Australia decreasing or increasing over time?

Are the number of deaths through assaults per 100,000 persons higher in one state compared to another?
Crime Victimisation, Australia (cat. no. 4530.0)Presents summary statistics about victims for a selected range of personal and household offences, regardless of whether these offences were reported to police.Annual (financial year basis)2008-09
2009-10
National and state and territory data (some capital city / balance of state data available for selected data items).Includes demographic information about the victims (such as age, sex, marital status, labour force status, main source of income). Also provides information about the characteristics of their most recent incident and whether the incidents were reported to police. Additional topics such as feelings of safety, social disorder and personal fraud are also included in the data, however these topics are not included on an annual basis.How many victims of physical assault are there in Australia (latest data available)?

What are the reporting rates for sexual assault in Australia?

Do unemployed persons have a greater chance of being a victim of crime in comparison to employed persons?

What items were most commonly stolen in incidents of break-in?
Personal Safety Survey (cat. no. 4906.0)Presents data on men’s and women’s experiences of violence, including physical or sexual assault or threat.Next results expected in 2013.2005National and state and territory dataInformation about men’s and women’s experiences of different types of violence, since the age of 15, by different types of male and female perpetrators (including current partner, previous partner, boyfriend / girlfriend or date, other known man or woman, and stranger). Additional information was also collected about respondents’ experience of current and previous partner violence, stalking, harassment and general feelings of safety.How many men / women have experienced physical assault by their current partner during the last 12 months?

How many men / women have experienced sexual assault by a stranger (in comparison to sexual assault from a known person) in the last 12 months?

How many men / women have experienced physical violence since the age of 15?

How many men / women were a victim of stalking since the age of 15?
General Social Survey: Summary Results, Australia, (cat. no. 4159.0)Presents data on a wide range of areas of social concern, such as health, housing, education, work, income, financial stress, broad assets and liabilities, transport, social capital, voluntary work, family and community, and crime.Every 4 years2002
2006
National and state and territory dataSummary data items relating to crime victimisation of physical or threatened violence against a person, and actual or attempted break-ins to homes, garages or sheds. Feelings of safety data items are also included. These data items can then be linked with other data items measuring areas of social concern in the survey, eg health measures with feelings of safety measures.Are feelings of safety related to other social factors such as health, income and housing?
National Aboriginal and Torres Strait Islander Social Survey, (cat. no. 4714.0)Presents data on a range of areas of social concern for Indigenous Australians, such as language and culture, health, education, financial stress and law and justice.Irregular2002
2008
National, state and territory and remoteness area.Summary data items relating to crime victimisation of physical or threatened violence against a person within the last 12 months, contact with police since the age of 15 and use of legal services in the last 12 months. Also contains basic data on neighbourhood and community problems.How many Aboriginal and Torres Strait Islander persons were a victim of physical or threatened assault?

What proportion of Aboriginal and Torres Strait Islander persons sought the use of legal services in the last 12 months?

Which data source do I use?

Generally, the administrative data sources are most useful for providing a view of crime victimisation that is coming to the attention of the Criminal Justice System and can subsequently become the focus of investigation and other police actions. It is this recorded crime to which operational managers and policy makers are able to respond most effectively. The survey data sources vary in the crime data information available, but generally provide more coverage and detail than the administrative data sources, and are better suited to detailed analysis, extensive use of demographic variables or national level analysis. For example, when looking for data to support research into incidents of current partner violence and the impact that this has on victims' lives, the Personal Safety Survey would be the best source. 

Other measures of data quality can be used to assess different sources of statistical information. The ABS assesses the fitness-for-purpose of data sources using the ABS Quality Framework. The framework contains six dimensions of quality that should be considered when choosing a data source: relevance, accuracy, timeliness, accessibility, interpretability and coherence. These dimensions are discussed in the Data Quality Declarations for each data source. Users should also refer to Methodology in publications in order to assess the usefulness of the data for their purposes.

Ultimately, the choice of which data source to use should be an informed decision made by the user based on the specific research questions to be answered, an understanding of the purpose of the data source and associated underlying methodology.

Conclusion - chapter 4

The key to using crime victimisation data accurately is to thoroughly understand the data source and make informed decisions about which data source to use to meet particular data requirements.

The aim of this paper has been to increase community understanding of how the experiences of victims of crime in Australia are measured and to explore why the findings from different data sources can produce different results. A discussion of the advantages and disadvantages of survey and administrative data collection highlighted the key issues to be aware of when using either data source. A working example of comparisons between different data sources was used to demonstrate the impact of varying data collection methodologies on data for a range of offence types. Guidance about which data source is best suited to particular research questions was also provided.

Technical note

Data quality - survey data

Reliability of the estimates

1 Since the estimates from the Crime Victimisation Survey are based on information obtained from a sample of persons, they are subject to sampling variability. That is, the estimates may differ from those that would have been produced had all persons been included in the survey.

2 One measure of the likely difference is given by the standard error (SE), which indicates the extent to which an estimate might have varied by chance because only a sample of persons was included. There are about two chances in three (67%) that a sample estimate will differ by less than one SE from the number that would have been obtained if all persons had been surveyed, and about 19 chances in 20 (95%) that the difference will be less than two SEs.

3 Another measure of the likely difference is the relative standard error (RSE), which is obtained by expressing the SE as a percentage of the estimate.

\(R S E \%=\left(\frac{S E}{e s t i m a t e}\right) \times 100\)

4 Only estimates (numbers or percentages) with RSEs less than 25% are considered sufficiently reliable for most analytical purposes. However, estimates with larger RSEs have been included. Those estimates with an RSE greater than 25% are preceded by an asterisk (e.g. *2.2) to indicate they are subject to high SEs and should be used with caution. Estimates with RSEs greater than 50% are preceded by a double asterisk (e.g. **1.5) to indicate that they are considered too unreliable for general use.

Calculation of standard errors

5 Standard errors can be calculated using the estimates (numbers or percentages) and the corresponding RSEs. For example, the estimated number of persons who reported to police that they were victims of physical assault in the last 12 months in New South Wales was 75,000. The RSE for this estimate is 14.8%. The SE is calculated by:

\(\begin{aligned} & \text {SE of estimate} \\\\=&\left(\frac{R S E \%}{100}\right) \times \text { estimate } \\\\=& 0.148 \times 75,000 \\\\=& 11,100 \end{aligned}\)

6 Therefore, there are about two chances in three that the value that would have been produced if all dwellings had been included in the survey will fall within the range 63,900 to 86,100 and about 19 chances in 20 that the value will fall within the range 52,800 to 97,200. This example is illustrated in the diagram below:

Diagram showing the 95% and 68% confidence intervals for a published estimate.
The published estimate is 75,000. There are two chances in three that the true value is in the range of 63,900 to 86,100, and 19 chances in 20 that the true value is in the range of 52,800 to 97,200.

Significance testing

7 A statistical significance test for a comparison between survey estimates can be performed to determine whether it is likely that there is a difference between the corresponding population characteristics. The standard error of the difference between two corresponding estimates (x and y) can be calculated using the formula in paragraph 5. This standard error is then used to calculate the following test statistic:

\(\large{\left(\frac{x-y}{SE(x-y)}\right)}\)

8 If the absolute value of this test statistic is greater than 1.96 then the two estimates are said to be statistically significantly different at the 5% level: that is, there is less than 5% chance that the two estimates could have differed by as much as was observed had there been no difference in the two population characteristics. Otherwise, it cannot be stated with confidence that there is a real difference between the populations with respect to that characteristic.

9 For further information about the data quality of the Crime Victimisation Survey, please refer to Crime Victimisation, Australia.

Data quality - administrative data

Offence coding

10 The offence categories used for the 2008 reference period for Recorded Crime – Victims are based on the Australian Standard Offence Classification, 1997 (cat. No. 1234.0) (ASOC97). The offence categories used for the 2009 reference period are based on the Australian Standard Offence Classification, 2008 (second edition) (cat. No. 1234.0) (ASOC08). ASOC provides a uniform national statistical framework for classifying offences.

11 The introduction of ASOC08 had limited impact on the Recorded Crime – Victims data due to minimal change to the activities included or excluded for the selected offences published for the collection. The primary impact was on the offence category of other theft, with data relating to fare evasion coming into scope of the collection. Other theft was not included in the analysis in this paper and the impact on the remaining offence types was limited.

12 During the course of the revised classification being implemented, jurisdictions also rectified a number of local offence codes that were miscoded to ASOC in previous years, thus impacting on data comparability between 2009 and prior years for certain offences. This has primarily affected the offence categories of other theft and assault for a number of jurisdictions resulting in increased victim counts.

Outcomes of investigation

13 Within Recorded Crime – Victims, the stage that a police investigation has reached after a period of 30 days has elapsed since the recording of the incident by police is referred to as the outcome of investigation.

14 Data for the 2008 reference period includes counts for outcomes of investigations that were determined as 'no crime', where these can be identified, with the exception of Queensland. The impact of this on the analysis presented in this paper is minimal due to the small proportion of 'no crimes' for the selected offences presented for the remaining jurisdictions that included no crimes in the recorded crime data.

15 Data for the 2009 reference period excludes counts for outcomes of investigations that were determined as ‘no crime’, where these can be identified. The removal of this has resulted in a reduction of victim counts in comparison to 2008, in those jurisdictions where where these counts had been included. Queensland data are not impacted as these outcomes were not included in prior years. Due to systems issues, data for the Northern Territory continues to include these outcomes. The impact of excluding 'no crime' counts from the data for 2009 has led to decreases in victim counts ranging from -0.2% to -9.3%. Most changes are below 5%.

16 For further information about the data quality of the police recorded crime data, please refer to Recorded Crime – Victims, Australia

Data confrontation methodology

17 When undertaking any sort of comparisons between data sets, it is imperative to understand the differences between the sources such as the scope of the data, how the data is collected, counting rules applied and definitions employed. The table below outlines the key metadata for the Recorded Crime – Victims and Crime Victimisation, Australia datasets.

Broad comparisons between data sources

Broad comparisons between data sources

CollectionRecorded Crime – Victims, AustraliaCrime Victimisation, Australia
Collection ModeInformation on victimisation is collected by the ABS in aggregate form from administrative records held by police agencies within each state and territory.The Crime Victimisation Survey is conducted using the Multipurpose Household Survey vehicle (MPHS). Data is collected using Computer Assisted Interviewing (CAI) whereby responses are recorded directly onto an electronic questionnaire in a notebook computer, usually during a telephone interview.
Counting UnitThe counting unit for the Recorded Crime – Victims collection is "victim". A victim can be a person, an organisation, a premise/place, or a motor vehicle, depending upon the offence. Victims who were recorded by police only are included in this collection.There are two counting units for the survey:
1. victim - a victim can be either a person who is usually resident in a private dwelling, or a household.
2. incident – a single occurrence of a crime event. Victims can report multiple incidents, which means the total number of victims and total number of incidents will differ.
Reference PeriodRecorded Crime – Victims data is collected on a calendar year basis. Data are compiled using the date an offence is reported to police and recorded within a reference period. This corresponds to either the date the offence was reported to police by a member of the public or when it was detected by police. The report date may not necessarily be the date when the offence occurred. This is particularly the case for homicide and related offences and sexual assault offences, where in some instances the time difference between when the offence occurred and the report/detection date may be substantial.The survey enumeration period spans 12 months on a financial year basis, from the 1st July through to the 30th June. Respondents are asked about their experience of crime within the 12 months prior to the survey interview.
ScopeThe scope of Recorded Crime – Victims 2008 and 2009 includes victims of offences classified to selected divisions and/or subdivisions of ASOC97 and ASOC08 respectively.

With the exception of motor vehicle theft, statistics relate to both completed and attempted offences, that is, those where the intent is not fulfilled. Attempted motor vehicle thefts are excluded from the scope of the collection due to difficulties in distinguishing these offences from criminal damage.

The scope excludes the following: - Conspiracy offences
- Threats to commit an offence. An exception to this exclusion is assault where there is an apprehension that the direct threat of force, injury, or violence could be enacted. Also, for offences like robbery, kidnapping / abduction and blackmail / extortion wherein an element of threat is implicit in the nature of the crime.
- Aid, abet and accessory offences
- Deprivation of liberty offences
Offences may include those that at a later point in time were determined to be unfounded, ie false or baseless. From 2009, these counts are excluded from the data.

Some victims of minor offences may not be recorded on crime recording systems by police in all states and territories.
The Crime Victimisation Survey is a survey of all persons aged 15 years and over, with the exception of sexual assault which is asked only of persons aged over 18 years, and excludes the following:

· members of the permanent defence force
· certain diplomatic personnel of overseas governments,
· overseas residents in Australia, and
· members of non-Australian defence forces (and dependents)
· people living in very remote parts of Australia
· people living in non-private dwellings such as hotels, university residences, students at boarding schools, patients in hospitals, residents of homes (eg retirement homes, homes for persons with disabilities, women’s shelters), and inmates of prisons.

The exclusion of people living in very remote areas is unlikely to impact on state and territory estimates, except in the Northern Territory where they account for approximately 23% of the total population.

Persons who were living in Indigenous communities in non-very remote areas are not covered for operational reasons.
Selected offence typesSelected offences included in the Recorded Crime – Victims collection are: - homicide and related offences (including murder, attempted murder and manslaughter, but excluding driving causing death and conspiracy to murder)
- assault
- sexual assault
- kidnapping / abduction
- robbery
- blackmail / extortion
- unlawful entry with intent (UEWI)
- motor vehicle theft
- other theft
Selected offences included in the Crime Victimisation Survey are: - physical assault
- threatened assault
- sexual assault
- robbery
- break in
- attempted break in
- motor vehicle theft
- other theft
- malicious property damage
Multiple offencesThe Recorded Crime – Victims collection does not enumerate unique persons or organisations. If a person is a victim of one offence, they will be counted once. If a person is a victim of multiple offences that fall within the same ANZSOC division, the victim is counted once, and the lowest ANZSOC code recorded within that division is recorded as the offence. If a person is a victim of the same offence multiple times on the same day, the victim is counted once. If a person is a victim of multiple offences that fall in different ANZSOC divisions, the victim is counted once in each of the different divisions, meaning one victim can be presented multiple times under different offence divisions.Victims are counted once for each separate offence type they have experienced. Multiple instances of the same offence type will be counted as multiple incidents (see information under counting unit)

Adjustments made to account for data source differences

Counting unit

18 For both data sources, the counting unit used for the analysis was the victim. For the Recorded Crime – Victims data, the victim count was restricted to persons, households and motor vehicles (for motor vehicle theft). Organisation data was excluded from the analysis as organisations were not in scope for the Crime Victimisation Survey. For the Crime Victimisation Survey data, only victims who stated the incident was reported to police was included in this analysis.

Reference period

19 Recorded Crime – Victims data is collected in reference to a calendar year while the Crime Victimisation Survey is collected on a financial year basis. As such, comparisons between the data sources have been approximated by using the calendar year reference period for the Recorded Crime – Victims data, with the financial year data for the Crime Victimisation Survey data. This approach was used by the UK Home Office (Smith and Hoare, 2009) in comparing the British Crime Survey with police recorded crime.

20 The diagram below is a graphical representation of this methodology using the 2008 Recorded Crime – Victims reference period and the 2008-09 Crime Victimisation Survey data reference period as an example.

Graphical representation of the adjusted Recorded Crime – Victims reference period so that it better aligns with the Crime Victimisation Survey reference period.
Diagram shows the 2008 Police Recorded Crime calendar year reference period running from January 2008 to December 2008. Also shown is the month of interview for the 2008-09 Crime Victimisation Survey, with the 12 month reference period for respondents running from July 2007 to May 2009. The month of June is highlighted as the mid-point for survey estimates.


21 The 2008 Recorded Crime – Victims data refers to reports made to police, or an offence being detected by police, between January and December 2008. The 2008-09 Crime Victimisation Survey data refer to the 12 month period prior to the respondent participating in the survey. This means that the potential span of data from the survey ranges from July 2007 (the earliest offence date for respondents who were interviewed in July 2008, ie 12 months prior to interview) to June 2009 (the latest offence date for respondents who were interviewed in June 2009). The centre point to the survey recall period is June 2008, as this is a month which overlaps for all respondents. June 2008 is also the centre point of the Recorded Crime – Victims data. As such, the 2008-09 data for the Crime Victimisation Survey data and the 2008 Recorded Crime – Victims data are considered a suitable approximation for comparison.

Scope

Age

22 Recorded Crime – Victims data has been restricted to victims aged 15 years and over for general offence types and 18 years and over for sexual assault, to align with the scope of the Crime Victimisation Survey. For instances where the age of the victim was unknown, these records were also excluded as it could not be determined whether they should be in scope for the analysis.

Very remote areas

23 Recorded Crime – Victims data was adjusted for the Northern Territory to exclude victims living in very remote areas, to align with the scope of the Crime Victimisation Survey.

Offence types

24 Detailed information about how each offence type is defined in the data sources and any adjustments that were made for the data confrontation exercise are provided in the table below.

25 Note that homicide, kidnapping / abduction and blackmail / extortion are not included in the survey so were not part of the analysis in this paper. Likewise, attempted break in and malicious property damage were included in the survey but not included in the Recorded Crime – Victims collection. Other theft is included in both data sources, however due to significant definitional differences it was also excluded from analysis.

Broad Offence CategoryRecorded Crime – Victims, AustraliaCrime Victimisation SurveyAdjustments made for the analysis in this paper
AssaultThe direct (and immediate/confrontational) infliction of force, injury or violence upon a person or persons, or the direct (and immediate/confrontational) threat of force, injury or violence where there is an apprehension that the threat could be enacted.

Contains:
· Serious assault resulting in injury
· Serious assault not resulting in injury
· Common assault

(includes attempts and threats).

Can only be recorded against the person.
Physical Assault
An incident where anyone used physical force or violence against a respondent. Physical force or violence includes being: pushed, grabbed, shoved, slapped, hit with an open hand or fist, kicked or bitten. Includes assault in a respondents line of work and excludes incidents that occurred during the course of play on a sporting field and verbal abuse.

Threatened Assault
Includes any verbal and/or physical intent or suggestion of intent which the person believed was able and likely to be carried out.
Due to the survey design, reporting rates for non face-to-face assaults are not available. Therefore threatened assault data is unable to be included in the data confrontation. Physical assault data from the survey is used as an approximation of total assaults.

Attempted murder from the Recorded Crime Victims data has been added to the assault figures in the analysis presented in this paper. These incidents that are recorded as attempted murder, may have been included as physical force or violence in the survey.
Sexual AssaultPhysical contact, or intent of contact, of a sexual nature directed toward another person where that person does not give consent, gives consent as a result of intimidation or deception, or consent is proscribed.

Contains:
· Aggravated sexual assault
· Non-aggravated sexual assault
(includes attempts and threats).

Can only be recorded against the person.
Definition of sexual assault is based on the interpretation of the respondent. Only persons aged 18 years and over were asked questions about sexual assault.Victims of sexual assault aged under 18 years in Recorded Crime – Victims were removed to align with the scope of the survey.
RobberyThe unlawful taking of property, with the intent to permanently deprive the owner of the property, from the immediate possession, control, custody or care of a person or organisation, accompanied by the use, and / or threatened use, of immediate force or violence.

Contains:
· Aggravated robbery
· Non-aggravated robbery
(includes attempts and threats).

Can be recorded against a person or an organisation.
An incident where someone stole (or tried to steal) property from a respondent by physically attacking or threatening them with force or violence. Includes incidents of physical assault and threatened assault which also involved robbery or attempted robbery.Matched where possible, by attempting to identify and exclude organisations in Recorded Crime – Victims.
Unlawful entry with intent
(Break in)
The unlawful entry of a structure with the intent to commit an offence where the entry is either forced or unforced.

Can occur against a domestic or commercial premises.

Attempted unlawful entry is not included.
An incident where an offender broke into the respondent’s home (primary residence).

Includes only break-in to residential premises.

Attempted and actual break-in are collected separately.
Residential premises only are included from the Recorded Crime – Victims data, to align with the scope of the survey.
Motor Vehicle TheftThe taking of another person’s motor vehicle illegally and without permission with the intent of temporarily or permanently depriving the owner or possessor of the use of the motor vehicle. Excludes attempted motor vehicle theft

Contains:
· Theft of Motor Vehicle
· Illegal Use of Motor Vehicle

Private / business use cannot be determined from the Recorded Crime – Victims data.

Motor Vehicle is the counting unit.
An incident where a motor vehicle was stolen from any member of the household. Only includes vehicles where the primary use is for private purposes (ie excludes commercial vehicles).

Motor vehicle theft incidents are collected as household level data.
As the differentiation between private / business vehicles is unable to be determined using Recorded Crime – Victims data, there may be more vehicles included in the Recorded Crime – Victims data in comparison to the Crime Victimisation data which excludes commercial vehicles.

Illegal use of motor vehicle data is included for Recorded Crime – Victims as these incidents may be recorded within motor vehicle theft in the survey.

References

Show all

Australia Bureau of Statistics, 2011a, Causes of Death, Australia, 2009, cat. no. 3303.0, ABS, Canberra

Australian Bureau of Statistics, 2011b, Crime Victimisation, Australia 2009-10, cat. no. 4530.0, ABS, Canberra

Australian Bureau of Statistics, 2010a, Crime Victimisation Australia, 2008-09, cat. no. 4530.0, ABS, Canberra

Australian Bureau of Statistics, 2010b, Recorded Crime - Victims, Australia, 2009, cat. no. 4510.0, ABS, Canberra

Australian Bureau of Statistics, 2009a, National Aboriginal and Torres Strait Islander Social Survey, 2008, cat. no. 4714.0, ABS, Canberra

Australian Bureau of Statistics, 2009b, Recorded Crime - Victims, Australia, 2008, cat. no. 4510.0, ABS, Canberra

Australian Bureau of Statistics, 2007, General Social Survey, Summary Results, Australia 2006, cat. no. 4159.0

Australian Bureau of Statistics, 2006, Personal Safety Survey, 2005, cat. no. 4906.0, ABS, Canberra

Australian Bureau of Statistics, 2004, Information Paper: Measuring Crime Victimisation, Australia: The Impact of Different Collection Methodologies, 2002, cat. no. 4522.0.55.001, ABS, Canberra

Coleman, C. & Moynihan, J. 1996, Haunted by the dark figure: criminologists as ghostbusters?’ In, Maguire. M. (ed), Understanding Crime Data: Haunted by the dark figure, Open University Press, Buckingham UK.

Mouzos, J. 2003, Australian Homicide Rates: A comparison of three data sources, Australian Institute of Criminology, Canberra

Smith, K. and Hoare, J. 2009, Crime in England and Wales 2008-09, Volume 2: Explanatory Notes and Classifications, Crown, London.

Statistics Canada 1997, An overview of the differences between police-reported and victim-reported crime, Canada.

Abbreviations

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ABBREVIATIONS

ABSAustralian Bureau of Statistics
ACTAustralian Capital Territory
ASOCAustralian Standard Offence Classification
ANZSOCAustralian and New Zealand Standard Offence Classification
cat. no.Catalogue number
GSSGeneral Social Survey
MPHSMultipurpose Household Survey
NATSISSNational Aboriginal and Torres Strait Islander Social Survey
NCRSNational Crime Recording Standard
NCCJSNational Centre for Crime and Justice Statistics, Australian Bureau of Statistics
NSWNew South Wales
NTNorthern Territory
PSSPersonal Safety Survey
QldQueensland
SASouth Australia
Tas.Tasmania
Vic.Victoria
WAWestern Australia

Previous catalogue number

This release previously used catalogue number 4500.0.55.001