|
|
EXPLANATORY NOTES
INTRODUCTION
1 The statistics presented in this release were compiled from data collected in the Australian Bureau of Statistics' (ABS) 2013-14 Multipurpose Household Survey (MPHS). The MPHS is conducted each financial year throughout Australia from July to June as a supplement to the ABS' monthly Labour Force Survey (LFS) and is designed to provide annual statistics for a number of small, self-contained topics.
2 In 2013-14 the topics were:
- Barriers and Incentives to Labour Force Participation
- Retirement and Retirement Intentions (including Method of Meeting Current Living Costs)
- Household Use of Information Technology
- Patient Experience
- Family Transitions and History
- Family Characteristics
- Crime Victimisation
- Income (Personal, Partner's, Household).
3 For all topics, general demographic information such as age, sex, labour force characteristics, education and income are also available.
4 This publication covers the Crime Victimisation Survey topic and presents details about victims of a selected range of personal and household crimes, whether victims reported these incidents to police, the characteristics of victims and the characteristics of their most recent incident. Some estimates from the 2008–09, 2009–10, 2010–11, 2011-12, and 2012-13 Crime Victimisation Surveys are also included in this publication.
5 Crime victimisation data are again being collected in the MPHS for the reference period 2014–15, with that data expected to be available in early 2016.
SCOPE
6 The scope of the Labour Force Survey (LFS) is restricted to people aged 15 years and over and excludes the following:
- members of the permanent defence forces
- certain diplomatic personnel of overseas governments usually excluded from census and estimated resident populations
- overseas residents in Australia
- members of non-Australian defence forces (and their dependants).
7 In addition, the 2013–14 MPHS excluded the following from scope:
- Households in Indigenous communities
- people living in non-private dwellings (e.g. hotels, university residences, students at boarding schools, patients in hospitals, inmates of prisons and residents of other institutions (e.g. retirement homes, homes for persons with disabilities).
COVERAGE
8 In the LFS, coverage rules are applied which aim to ensure that each person is associated with only one dwelling and hence has only one chance of selection in the survey. See Labour Force, Australia (cat. no. 6202.0) for more details.
9 In the LFS, rules are applied which aim to ensure that each person in coverage is associated with only one dwelling and hence has only one chance of selection in the survey. See Labour Force, Australia (cat. no. 6202.0) for more details.
DATA COLLECTION
10 The MPHS was conducted as a supplement to the monthly LFS. Each month one eighth of the dwellings in the LFS sample were rotated out of the survey. In 2013-14, all of these dwellings were selected to respond to the MPHS each month. In these dwellings, after the LFS had been fully completed for each person in scope and coverage, a person aged 15 years and over was selected at random (based on a computer algorithm) and asked the various MPHS topic questions in a personal interview. If the randomly selected person was aged 15–17 years, permission was sought from a parent or guardian before conducting the interview. If permission was not given, the parent or guardian was asked the crime questions on behalf of the 15–17 year old. Questions relating to sexual assault, alcohol or substances contributing to the most recent physical or face-to-face threatened assault were not asked of proxy respondents. Only those persons aged 18 years and over were asked questions on sexual assault. Data was collected using Computer Assisted Interviewing, whereby responses were recorded directly onto an electronic questionnaire in a notebook computer, usually during a telephone interview.
11 For the 2013-14 MPHS, the sample was accumulated over a 12 month period from July 2013 to June 2014.
12 The publication Labour Force, Australia (cat. no. 6202.0) contains definitions of demographic and labour force characteristics, and information about telephone interviewing that is relevant to both the monthly LFS and MPHS.
Sample size
13 The initial sample for the crime victimisation topic was 42,102 private dwellings, from which one person was randomly selected. Of the 35,904 private dwellings that remained in the survey after sample loss (for example, dwellings selected in the survey which had no residents in scope for the LFS, vacant or derelict dwellings and dwellings under construction), 27,327 or 76% fully responded to the questions on crime victimisation.
ESTIMATION METHOD
Weighting
14 Weighting is the process of adjusting results from a sample survey to infer results for the total in-scope population. To do this, a 'weight' is allocated to each sample unit, which, for the MPHS, can be either a person or a household. The weight is a value which indicates how many population units are represented by the sample unit. For the MPHS, the first step in calculating weights for each unit was to assign an initial weight, which is the inverse of the probability of being selected in the survey. For example, if the probability of a person being selected in the survey was 1 in 600, then the person would have an initial weight of 600 (i.e. they represent 600 people).
Benchmarking
15 The initial weights were then calibrated to align with independent estimates of the population of interest, referred to as 'benchmarks', in designated categories of age by sex by area of usual residence. Weights calibrated against population benchmarks ensure that the survey estimates conform to the independently estimated distribution of the population rather than the distribution within the sample itself. Calibration to population benchmarks helps to compensate for over or under-enumeration of particular categories of persons/households which may occur due to either the random nature of sampling or non-response.
16 For person estimates, the MPHS was benchmarked to the projected population in each state and territory, as at 31 March 2014. For household estimates, the MPHS was benchmarked to independently calculated estimates of the total number of households in Australia. The MPHS estimates do not (and are not intended to) match estimates for the total Australian person/household populations obtained from other sources.
Estimation
17 Survey estimates of counts of persons or households are obtained by summing the weights of persons or households with the characteristic of interest. Estimates of non-person counts (e.g. number of attempted break-ins) are obtained by multiplying the characteristic of interest with the weight of the reporting person/household and then aggregating them.
Confidentiality
18 To minimise the risk of identifying individuals in aggregate statistics, a technique is used to randomly adjust cell values. This technique is called perturbation. Perturbation involves a small random adjustment of the statistics and is considered the most satisfactory technique for avoiding the release of identifiable statistics while maximising the range of information that can be released. These adjustments have a negligible impact on the underlying pattern of the statistics. After perturbation, a given published cell value will be consistent across all tables. However, adding up cell values to derive a total will not necessarily give the same result as published totals. Perturbation has only been applied to the 2013–14 data.
19 For data from previous cycles (2008-09 to 2012–13) table cells containing small values only were randomly adjusted to avoid releasing confidential information. Due to this randomisation process, totals may vary slightly across tables. These adjustments do not impair the value of the tables as a whole.
RELIABILITY OF ESTIMATES
20 All sample surveys are subject to error which can be broadly categorised as either:
- sampling error
- non-sampling error.
Sampling error
21 Sampling error is the difference between the published estimates, derived from a sample of persons, and the value that would have been produced if the total population (as defined for the scope of the survey) had been included in the survey. For more information refer to the Technical Note.
Non-sampling error
22 Non-sampling error may occur in any collection, whether it is based on a sample or a full count such as a census. Sources of non-sampling error include non-response, errors in reporting by respondents or recording of answers by interviewers and errors in coding and processing data. Every effort is made to reduce non-sampling error by careful design and testing of questionnaires, training and supervision of interviewers, and extensive editing and quality control procedures at all stages of data processing.
INTERPRETATION OF RESULTS
23 Crime victimisation surveys are best suited to measuring crimes against individuals or households with specific and identifiable victims. Victims need to be aware of and recall what happened to them and how it happened, as well as be willing to relate what they know to interviewers.
24 Not all types of crime are suitable for measurement by household surveys. No reliable information can be obtained about crimes without specific victims, such as trafficking in narcotics. Crimes of which the victim may not be aware cannot be measured effectively - some crimes involving deception and attempted crimes of many types may fall into this category. It may also be difficult to obtain information about some crimes such as sexual offences and assault committed by other household or family members due to the sensitivity of the crime and an increased reluctance to disclose. Some of these crimes may not be fully reflected in the data collected. Household survey data excludes crimes against commercial establishments or government agencies.
25 This survey covered only selected types of personal and household crimes. Personal crimes covered in the survey were physical assault, threatened assault, robbery and sexual assault. Household crimes covered were break-in, attempted break-in, motor vehicle theft, theft from a motor vehicle, malicious property damage and other theft.
26 For this survey the definition of total victims is restricted to those crimes included in the survey and does not represent all crime in Australia. Information collected in this survey is essentially 'as reported' by respondents and hence may differ from that which might be obtained from other sources or via other methodologies. This factor should be considered when interpreting the estimates and when making comparisons with other data sources.
Statistical measures of crime victimisation
27 The level of victimisation can be expressed in more than one way. The most common measure derived from crime victim surveys is prevalence, that is, the number of the relevant population that have been a victim of a given crime at least once in the reference period. This is known as the 'victimisation rate'. Victimisation rates used in this publication represent the prevalence of selected crimes in Australia, and are generally expressed as a percentage of the total relevant population. Reporting rates used in this publication are expressed as the percentage of victims whose most recent incident of each type of crime had been reported to the police.
DATA COMPARABILITY
28 The 2013-14 Crime Victimisation Survey is the sixth in a new series of regular Crime Victimisation Surveys conducted by the ABS. The five previous surveys in this series (conducted for the 2008–09, 2009–10, 2010–11, 2011-12, and 2012-13 reference periods) included many of the questions asked in 2013-14. This has enabled some time series comparisons to be made in this publication.
29 The Crime Victimisation Survey series replaced the previous Crime and Safety Surveys and was introduced because of a change to the collection methodology. The new method of collection mainly uses personal telephone interviews of selected respondents. Data collections between 1990 and 2005 required respondents to self complete questionnaires and mail these back to the ABS. This difference in mode of collection and changes to survey questions means that data collected using the MPHS is generally not directly comparable with data from previous years' Crime and Safety Surveys.
30 Since 1990, Crime and Safety Surveys were conducted by the ABS nationally and in specific states and territories at different times. Collections have taken place in the following years:
| Region | Collection reference periods prior to the 2008–09 Crime Victimisation Survey |
| New South Wales | 2008, 2007, 2006, 2004, 2003, 2001, 2000, 1999, 1997, 1996, 1995, 1994 |
| Victoria | 1995, 1994 |
| Queensland | 1995 |
| Western Australia | 1999, 1995, 1991 |
| South Australia | 2000, 1995, 1991 |
| Tasmania | 1998 |
| Australian Capital Territory | 1995 |
| Australia | 2005, 2002, 1998, 1993, 1983, 1975 |
31 Different crime statistics collections can yield different results. Caution should be taken when comparing data from different surveys and administrative by-product collections that relate to crime and justice issues. For more information on comparisons between sources, please refer to Measuring Victims of Crime: A Guide to Using Administrative and Survey data, June 2011 (cat. no. 4500.0.55.001).
Comparability with the 2008–09, 2009–10, 2010-11, 2011-12, and 2012-13 Crime Victimisation Survey
32 Most of the questions asked in the 2008–09, 2009–10, 2010–11, 2011-12, and 2012-13 Crime Victimisation Surveys have been repeated in 2013-14. As a similar methodology has been adopted for the surveys, data on the prevalence of personal and household crimes should be comparable across the periods.
33 In the 2008–09 Crime Victimisation Survey, data was not collected in July and August in New South Wales (to avoid overlap with the April 2008 NSW Crime and Safety Survey). In the 2009–10, 2010–11, 2011–12, 2012-13, and 2013-14 surveys, data was collected for the full 12 months, however this change does not impact on the comparability of the data.
34 A significant change was made to the area of usual residence data item in 2010–11. In the 2008–09 and 2009–10 crime victimisation publications, area of usual residence was classified as State Capital Cities and Balance of State/Territory. The Balance of State/Territory category comprised people usually resident in areas outside of the six state capital city Statistical Divisions (as defined in the Australian Standard Geographical Classification (ASGC) (cat. no. 1216.0)), including all residents of the Northern Territory (except those in very remote areas) and the Australian Capital Territory. For 2010–11, 2011–12, 2012-13, and 2013-14, the State capital cities category has been changed to Capital City and now includes all of the ACT and Darwin Statistical Division, while the Balance of State/Territory category now comprises people usually resident in areas outside of the eight capital city Statistical Divisions, excluding all residents in the ACT. The new definitions of Capital City and Balance of State/Territory, as published, result in area of usual residence not being comparable across the surveys. However, comparable Correspondences for these classifications are available on request (see Products and Services section below for further details).
35 Crime Victimisation Survey data for 'Capital City' and 'Balance of State/Territory' areas in 2008-09, 2009-10, 2011-12 and 2012-13 were based on Capital City and Balance of State/Territory boundaries contained in the Australian Statistical Geography Classification (ASGC). The Australian Standard Geographical Classification (ASGS), introduced in 2011, contained new boundaries for Greater Capital City Statistical Areas and Balance of State/Territory areas and these have been used for the first time in Crime Victimisation data for 2013-14. Data for 'Greater Capital City Statistical Areas' (GCCSA) and 'Balance of State/Territory' in 2013-14 are based on the relevant boundaries contained in the ASGS. Users should note that these boundaries differ from the 'Capital City' and 'Balance of State/Territory' boundaries contained in the ASGC. More information is available here.
36 Some minor changes to the survey questions have been made in recent cycles. For the 2011–12 survey testing revealed that some respondents were including verbal threats in the physical assault module despite the question specifically referring to physical force or violence. From the 2011–12 survey, respondents were specifically instructed to exclude verbal abuse. Testing also found that some respondents were including bicycles and caravans in motor vehicle theft, which are not defined as motor vehicles for the purposes of the survey. In response, since the 2011–12 survey, respondents are asked explicitly to exclude theft of caravans, trailers and bicycles and theft of vehicles used mainly for business from the motor vehicle theft module. Due to the increase in ownership of iPads and other tablets, from the 2013-14 survey, respondents were asked to include these items in the "personal electronic equipment" category for robbery, theft from a motor vehicle and other theft and the "computer equipment" category for break-in and attempted break-in.
Comparability with police statistics
37 Data for selected crimes recorded by police agencies are available in Recorded Crime - Victims, Australia (cat. no. 4510.0). The Crime Victimisation Survey provides an additional source of data on crime victimisation for the selected crimes, including crime not reported to or detected by police. This survey identifies the nature of this unreported crime, as well as giving information about victims of repeated crimes. The information from the survey should be viewed as complementary to police recorded crime statistics.
38 The terms used for the crimes (such as robbery and physical assault) may not necessarily correspond with the legal or police definitions used. This is because responses obtained in this survey are based on the respondent's perception of being the victim of a crime. The definitions of terms used in the survey are based on the wording of the questions asked of the respondent and specifications provided to interviewers. Definitions of crime types included in this survey can be found in the Glossary.
39 The Crime Victimisation Survey collects information on crimes that were reported to police, as well as those which police did not become aware of. In this publication, reporting rates are based on whether or not the most recent incident of each crime type experienced by respondents in the 12 months prior to interview were reported to police. Interviews were conducted over a 12 month period from 1 July 2013 and 30 June 2014. The actual reference period for a particular respondent was determined by the date of their interview. There is no verification a crime report has actually been made for the crime if a survey respondent indicates that police were informed about the incident.
40 Another source of variation between the survey results and crimes recorded by police relates to differences in scope. This survey collects information on the personal crimes of physical assault, threatened assault and robbery for all people aged 15 years and over, and sexual assault for people aged 18 years and over. In contrast, police statistics include victims of all ages and any comparisons need to allow for this difference. Furthermore, police record all crimes reported to them in the reference period, whether or not the incidents took place during that period or at an earlier time.
Comparability with monthly LFS Statistics
41 Due to differences in the scope and sample size of the MPHS and that of the LFS, the estimation procedure may lead to some small variations between labour force estimates from this survey and those obtained from the LFS.
Other methodological issues
42 When interpreting data from the 2013-14 MPHS, consideration should be given to the representativeness of the sample. This is affected by the response rate and scope and coverage rules. For example, people living in boarding houses, refuges or on the streets are excluded from this survey and may experience different levels of victimisation than those surveyed, who live in private dwellings.
EQUIVALISED WEEKLY HOUSEHOLD INCOME
43 Equivalence scales are used to adjust the actual incomes of households in a way that enables the analysis of the relative well-being of people living in households of different size and composition. For example, it would be expected that a household comprising two people would normally need more income than a lone person household if all the people in the two households are to enjoy the same material standards of living. Adopting a per capita analysis would address one aspect of household size difference, but would address neither compositional difference (i.e. the number of adults compared with the number of children) nor the economies derived from living together.
44 When household income is adjusted according to an equivalence scale, the equivalised income can be viewed as an indicator of the economic resources available to a standardised household. For a lone person household, it is equal to income received. For a household comprising more than one person, equivalised income is an indicator of the household income that would be required by a lone person household in order to enjoy the same level of economic well-being as the household in question.
45 The equivalence scale used in this publication was developed for the Organisation for Economic Co-operation and Development and is referred to as the 'modified OECD' equivalence scale. It is widely accepted among Australian analysts of income distribution.
46 The scale allocates 1.0 point for the first adult (aged 15 years and over) in a household; 0.5 for each additional adult; and 0.3 for each child. Equivalised household income is derived by dividing total household income by the sum of the equivalence points allocated to Australian household members. For example, if a household received combined gross income of $2,100 per week and comprised two adults and two children (combined household equivalence points of 2.1), the equivalised gross household income would be calculated as $1,000 per week.
47 For more information on the use of equivalence scales, see Household Income and Distribution, Australia (cat. no. 6523.0).
CLASSIFICATIONS
48 Australian geographic data are classified according to the Australian Statistical Geography Standard (ASGS): Volume 1 - Main Structure and Greater Capital City Statistical Areas, July 2011 (cat. no. 1270.0.55.001).
49 Country of birth data are classified according to the Standard Australian Classification of Countries (Second Edition) (SACC), 2011 (cat. no. 1269.0).
50 Educational attainment data are classified according to the Australian Standard Classification of Education (ASCED), 2001 (cat. no. 1272.0).
PRODUCTS AND SERVICES
Spreadsheets
51 All tables, in Excel spreadsheet format, can be accessed from Downloads. The spreadsheets present tables of count person and proportion estimates, and their corresponding relative standard errors.
Data available on request
52 A further option for accessing data from the Crime Victimisation Survey is to contact the National Information and Referral Service. A range of additional data not provided in the standard spreadsheets may be provided on a fee-for-service basis through ABS Information Consultancy. A spreadsheet containing a complete list of the data items available from the Crime Victimisation Survey can be accessed from Downloads.
ACKNOWLEDGEMENTS
53 ABS surveys draw extensively on information provided freely by individuals, businesses, governments and other organisations. Their continued cooperation is very much appreciated. Without it the wide range of statistics published by the ABS would not be available. Information received by the ABS is treated in strict confidence as required by the Census and Statistics Act 1905.
RELATED INFORMATION
54 The Related Information tab associated with this release contains links to a selected range of ABS Crime and Justice publications. |
|
|
Quality Declaration 
Print Page
Print All