9309.0 - Motor Vehicle Census, Australia, 31 Mar 2010 
Quality Declaration
Quality Declaration ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 01/02/2011
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EXPLANATORY NOTES
2009, 31 March 1997, 31 October 2008, 31 March 1996, 31 October 2007, 31 March 1995, 30 May 2006, 31 March 1993, 30 June 2005, 31 March 1991, 30 September 2004, 31 March 1988, 30 September 2003, 31 March 1985, 30 September 2002, 31 March 1982, 30 September 2001, 31 March 1979, 30 September 1999, 31 October 1976, 30 September 1998, 31 October 1971, 30 September SCOPE 3 The Motor Vehicle Census includes all vehicles registered with a state or territory motor vehicle registry for unrestricted use on public roads with the following exceptions:
4 Vehicles on register are defined as those vehicles registered at the date of the census, or which had registration expire less than one month before that date. 5 Motor vehicle registration statistics are derived from data made available by various state and territory motor vehicle registration authorities and reflect the information as recorded in registration documents. 6 Vintage and veteran vehicles are excluded from vehicle counts in the published data, but are available for consultancy data requests. These vehicles are identified using a unique insurance code, with the following exceptions:
7 The estimated proportion of motor vehicles, excluding motor cycles, taken off the register since the previous MVC is referred to as the attrition rate. The attrition rates in the following table have been calculated using Motor Vehicle Census and New Motor Vehicle Sales data. Motor cycles are excluded from the attrition rate calculation as they are not included in New Motor Vehicle Sales data.
METHODOLOGY 8 The 2010 Motor Vehicle Census is a count of all in-scope vehicles registered with a state or territory motor vehicle registration authority (MVR) at 31 March 2010. The Australian Bureau of Statistics (ABS) receives the data from the individual motor vehicle registration authorities. At this stage all records are compared to the previous MVC data for vehicles that match (on-going registrations) and relevant details are updated for these vehicles. The matching is based primarily on a unique identifier given by the registries to each record. After the primary match is done, a secondary match is run based on the Vehicle Identification Number (VIN), engine number and chassis number to improve the number of matched records. 9 The unmatched records (new vehicle registrations) undergo editing of such items as bodycode, make, model, year of manufacture, weight, heavy vehicle code, postcode and fuel. See Technical Note 1: 2010 System and Processing Changes. 10 The editing of on-going registrations is limited as these records have been edited in past years. Aggregate data is checked across time, states and vehicle types to ensure coherency. DATA QUALITY 11 The size of the registered motor vehicle fleet (over 16 million vehicles) dictates that quality assurance of each record is not possible. Considerable effort is made, both by motor vehicle registration authorities and the ABS, to improve data quality. This is achieved through internal checks to ensure the vehicle counts track consistently in a time series when compared to previous MVCs. However, there remains some variation in the reporting from different state and territory registries and hence care should still be taken when comparing data across jurisdictions. 12 While the data are made available at a detailed level, the quality of this detailed data is less certain, therefore the ABS is unable to guarantee that it is necessarily sufficient for all purposes for which it is used. 13 Each year, for new vehicle registrations, vehicle model description for each Registry is converted to a standard ABS model. This is necessary as model descriptions can vary between Registries. Some vehicles have a blank model and these are coded to 'model unknown'. See Technical Note 1: 2010 System and Processing Changes for more detail. Data confrontation 14 There are no data sources available in which to directly assess the quality of MVC data, new motor vehicle sales data and population data provide an indication of data quality as they give some context to the size of the motor vehicle fleet. Assessing the quality of data by comparison against other datasets is known as data confrontation. The ABS has been using sales of new motor vehicles data and estimated resident population (ERP) data to 'confront' MVC data for several years. New Motor Vehicle Sales (NMVS) 15 Sales of new motor vehicles can be compared with data from the MVC based upon the year of manufacture. The following assumptions have been made:
16 Therefore, it can be assumed that vehicles manufactured in 2009 (as reflected in 2010 MVC data) would most likely have been sold in the period between 1 April 2009 and 31 March 2010 (as captured by sales of new motor vehicles data). Similarly, vehicles manufactured in 2008 would have been sold between 1 April 2008 and 31 March 2009, and so on. 17 Figures for NMVS by year have shown to be generally comparable with the number of registered vehicles by year of manufacture on the MVC. Estimated Resident Population (ERP) 18 Over the past few years, strong motor vehicle sales have meant that the growth in motor vehicle registrations has been higher than the growth in ERP. However, growth in MVC and ERP has tended to be in the same direction. STATISTICAL GEOGRAPHY 19 Geographic data available from the MVC are postcode of owner and state or territory of registration. 20 If analysis of regional data based on postcodes is being undertaken, the following considerations need to be taken into account:
UPCOMING CHANGES TO THE MVC SNAPSHOT DATE 21 The MVC snapshot date has been 31 March since 2001. From 2011, the snapshot date will change to 31 January each year. This is due to a change in reference period for the Survey of Motor Vehicle Use (SMVU), for which the MVC provides the survey frame. The time period covered by the SMVU will be changed in 2011, from the 12 month period ending 31 October to the 12 month period ending 30 June. Therefore, the MVC snapshot date needs to occur earlier each year in order for the SMVU frame to be available when required. ACKNOWLEDGEMENT 22 This publication draws extensively on information provided freely by the state and territory motor vehicle registration authorities. Their continued cooperation is very much appreciated. Without it, many of the transport statistics published by the ABS would not be available. RELATED PUBLICATIONS AND PRODUCTS 23 Users may also wish to refer to the following publications and products which contain information relating to motor vehicles in Australia:
ABS DATA AVAILABLE ON REQUEST 24 As well as the statistics included in this publication, the ABS has other relevant data available on request. Inquiries should be made to the National Information and Referral Service on 1300 135 070. Document Selection These documents will be presented in a new window.
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