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 Engineering Construction Survey measures the value of all engineering construction work undertaken in Australia (including Australian Territorial Waters and External Territories) and provides estimates by state, commodity and sector (public and private). It does not include construction of buildings i.e. houses, offices etc. For building construction see Building Activity, Australia (cat. no. 8752.0).
The main output from the survey is the value of work done and is available at the State and Territory level by the type of construction. Projects are classified as private sector or public sector according to the expected ownership of the project at the time of completion and are classified to a category of construction without regard to end use. The value of Engineering construction activity reported excludes the cost of land, repair and maintenance activity, the value of any transfers of existing assets, installed machinery and equipment not integral to the structure and the expenses for relocation of utility services. The installation of machinery and equipment which is an integral part of a construction project is included (see Directory of Statistical Sources for additional details).
Data is collected from the primary contractor (not subcontractor) of projects and selections are made from any business which may undertake Engineering Construction activity.
The survey is run quarterly with reference periods ending on March, June, September and December each year. Data is published in Engineering Construction Activity, Australia (cat. no. 8762.0) which is released approximately 14 weeks after the end of the reference period.
The sample of businesses approached each quarter is between 3000 and 3500 taken from the ABS business register. The response rate is normally between 90-95% and data is imputed for non-responding units. Selected businesses report on all of the engineering projects they are undertaking. A project is classified to a category of construction (bridges, roads) rather than to its end use eg mining. Data is collected separately for operations in each state. The sample is augmented by supplementary units which are identified from coverage checks as undertaking significant engineering construction work. The classification of work done for Public Private Partnerships and Joint Ventures can pose problems and may be classified as private sector although eventual ownership of the asset may reside with the public sector.
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 the way the population frame is constructed. An ongoing coverage exercise is conducted to identify significant engineering projects which improves 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 engineering type such as the 'Value of Work Yet to be Done' for 'Recreation' 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 the last 2 - 3 quarters.
This data along with the value of work done on residential and non-residential buildings from Building Activity, Australia (cat. no. 8752.0) are the major source data used to compile the national accounts estimates for private gross fixed capital formation on dwellings, and other buildings and structures in Australia.
The collection has been undertaken since September 1986. From the September quarter 1999, the methodology of the survey was changed to use the ABS central business register which is stratified according to industry, using the Australian and New Zealand Standard Industrial Classification (ANZSIC) and employment. The most recent impact on the survey was the change in ANZSIC classification from ANZSIC93 to ANZSIC06 from the September 2007 quarter. There has been no break in series resulting from the implementation of this change.
The change of the Telstra Corporation from the public sector to the private sector in November 2006 impacted on the public sector and private sector estimates from March 2007 quarter. See the paper Future Treatment of Telstra in ABS Statistics, 2007 (cat. no. 8102.0). Caution should be taken when comparing data across this period.
Preliminary estimates of the data are available in Construction Work Done, Australia (cat. no. 8755.0) along with preliminary estimates of building activity data.
There are a number of derived statistics and data transformations published to aid interpretation of the data. These include chain volume estimates, trend and seasonally adjusted estimates as well as the original estimates. While current price (original) estimates reflect both price and volume changes, chain volume estimates measure changes in value after the direct effects of price changes have been eliminated and hence only reflect volume changes. For further information please refer to the Explanatory Notes.
Engineering Construction Activity (cat. no. 8762.0) contains Explanatory Notes and a Glossary which provide further information about data sources, terminology and other technical aspects of the series.