QUALITY DECLARATION - SUMMARY
For information on the institutional environment of the Australian Bureau of Statistics (ABS), including the legislative obligations of the ABS, financing and governance arrangements, and mechanisms for scrutiny of ABS operations, please see ABS Institutional Environment.
The Building Activity Survey is an activity based collection designed to measure the value of all construction work undertaken on buildings in Australia (including External Territories) and provide estimates by state and sector (public and private).
Building Activity includes construction of new buildings and alterations and additions to existing buildings. It does not include construction activities not defined as 'building' i.e. construction of roads, bridges, railways, earthworks etc. For non-building construction see Engineering Construction Activity, Australia (cat. no. 8762.0).
The main output from the survey is the value of work done for private or public sector according to the expected ownership of the building on completion and classified according to its intended major function. The value collected excludes the cost of land and normal repair and maintenance.
Data is collected from builders, other organisations and individuals engaged in building activity. Building jobs included each quarter comprise selected jobs which have not been completed in the previous quarter and newly selected jobs from approved building jobs notified to the ABS Building Approvals Collection (cat. no. 8731.0) during the 3 months up to, but not including, the last month of the reference quarter.
BACS is a quarterly survey run with reference periods ending on March, June, September and December each year. Data is published in Building Activity, Australia (cat. no. 8752.0) which is released approximately 14 weeks after the end of the reference period.
The sample of building jobs on which data is collected each quarter is between 25,000 and 30,000 depending on the amount of building activity in the economy and the speed at which jobs are completed. The response rate is normally between 90-95% and data is imputed for non-responding units.
Only building jobs valued at $10,000 or more for residential building and $50,000 for non-residential building are included in the survey. Building work not requiring approval from a reporting authority is not in scope of the survey. Consequently small alterations and additions, such as kitchen renovations which do not undertake structural changes to a building are not included in the survey.
There are two principal sources of error in surveys, sampling error and non-sampling error. Non-sampling error arises from inaccuracies in collecting, recording and processing the data. Every effort is made to minimise non-sampling error by the careful design and testing of questionnaires, detailed checking of the reported data and direct follow up with providers where significant errors are detected. At the time of selections there is some undercoverage due to building jobs not notified to Building Approvals in a timely manner by approving authorities. A quarterly coverage exercise is conducted to identify significant building jobs which improves the coverage.
Sampling error occurs when a sample or subset of the population is surveyed rather than the entire population. One measure of the likely difference resulting from not including all of the population in the survey is given by the relative standard error. The relative standard errors for the main published tables are small and therefore the estimates can be used with confidence. However, some estimates of finer breakdown in building type (e.g. Transport, other commercial n.e.c, agricultural/aquacultural, religious) should be used with caution. Further information on the reliability of estimates is available in the Explanatory Notes.
Revisions are made to the survey data as required as a result of new and updated information available from providers. Generally revisions are confined to previous quarter data.
BACS has been a quarterly survey since its commencement in the September quarter 1980. There have been various improvements to the collection over time including changes to the Functional Classification of Buildings, the inclusion of owner builders into the collection and the phasing in of modelling for small building jobs.
Comparison with Building Approval data can assist in measuring the flow from approval through to commencement and completion of building jobs. However, some jobs do not proceed after obtaining approval and these are eventually cancelled without ever having made a contribution to any Building Activity data item. The percentage of such jobs can be up to 3%.
Preliminary estimates of the data are available in Construction Work Done, Australia (cat. no. 8755.0) along with preliminary estimates of engineering construction activity data.
Data from the Building Activity Survey along with the value of work done on non-buildings (from the Engineering Construction Survey, Australia (cat. no. 8762.0)) are the major source data which are used to compile the national accounts estimates for private gross fixed capital formation on dwellings, and other buildings and structures in Australia. This provides a complete picture of building and construction activity in Australia, buildings and non-buildings. The number of dwelling unit commencements is also collected in the survey and is published in Dwelling Unit Commencements, Australia (cat. no. 8750.0).
Where possible buildings are classified according to their intended major end use function not to the function of the group to which it may be part. For example, an office building which is part of a manufacturing plant would be classified as an 'office' not a 'factory'. Where a building has multipurpose functions, such as retail outlets beneath residential accommodation, the ABS endeavours to report data according to each function. Where this is not possible, the building is classified according to the predominant function based on the total value of the project. Building jobs are also classified by type of work into 'new', 'alterations and additions' and 'conversions' etc. Further information is available in the Explanatory Notes.
Building Activity, Australia (cat. no. 8752.0) contains Explanatory Notes and a Glossary which provide further information about data sources, terminology and other technical aspects of the series.