TECHNICAL NOTE 1 2010 SYSTEM AND PROCESSING CHANGES
1 Significant changes have been made to the system and processing method for the 2010 Motor Vehicle Census (MVC). This technical note details the system changes and the impact these have had on the MVC data. These changes were introduced to accommodate an upcoming change in the MVC snapshot date and ensure the processing system can be maintained into the future.
DETAILS OF CHANGES
2 The ABS Survey of Motor Vehicle Use (SMVU) draws its frame from the MVC. From 2011, the SMVU reference period will be moving forward from the 12 months ending 31 October to the 12 months ending 30 June to improve usability for ABS clients. To facilitate this, the MVC snapshot date is being moved from 31 March to 31 January from 2011 as announced in ABS Information Paper: Changes to the Motor Vehicle Census date (ABS cat. no. 9309.0.55.002). To ensure the SMVU frame is available when required, processing time for the MVC has been reduced by improving processing systems and practices.
3 The specific changes made to the MVC system were:
- A significant reduction in manual individual record editing (microediting). Due to the volume of records, this has been a very time consuming process.
- Introduction of an autocorrection facility, to undertake the majority of changes which were previously done through microediting. MVC data is now corrected automatically where certain pre-defined logic is met.
- Identifying consistent make and model using information directly obtained from the Registries. This was previously identified by decoding the Vehicle Idenitification Number (VIN), which was a time consuming process to maintain.
- Removing the sub-model classification, which has not been routinely used in output.
- The number of codes used to classify bodycodes was reduced, with similar bodycodes being combined. Sedans and station wagons were combined as were utilities and cab-chassis.
The new system of MVC processing produces comparable aggregate data for significantly less effort when compared to previous MVCs. Autocorrections now correct the majority of records which would have been microedited in the previous system. The overall impact on aggregate data appears to be small. Similar estimates have been obtained by state and territory for 2010 as those which were obtained for 2009 (after accounting for historical growth). However, users should use caution when comparing more disaggregated data between 2009 and 2010.
The key impacts for users are:
- An increase in the proportion of "unknown" makes for Passenger Vehicles from 0.03% to 0.25% due to the removal of the VIN decoding system. This may improve in future as the ABS is able to identify and map these makes to standard ABS makes.
- Sub model will no longer be available for output.
- Bodycode classifications have changed as similar bodycodes have been combined.