TECHNICAL NOTE DATA QUALITY
1 The estimates in this release are based on information obtained from a sample survey (i.e. the Energy, Water and Environment Survey) conducted by the Australian Bureau of Statistics (ABS). Any collection of data can be affected by factors that affect the reliability of the resulting statistics, regardless of the methodology used. These factors result in non-sampling error. In addition to non-sampling error, sample surveys are also subject to inaccuracies that arise from the fact that a sample was selected rather than conducting a census. This type of error is called sampling error.
2 The majority of data contained in this publication have been obtained from a sample of businesses/organisations. As such, these data are subject to sampling variability, that is, they may differ from the figures that would have been produced if the data had been obtained from all businesses/organisations in the population. One measure of the likely difference is given by the standard error, which indicates the extent to which an estimate might have varied by chance because the data were obtained from only a sample of units. There are about two chances in three that a sample estimate will differ by less than one standard error from the figure that would have been obtained if all units had been included in the collection, and about nineteen chances in twenty that the difference will be less than two standard errors.
3 Sampling variability can also be measured by the relative standard error (RSE), which is obtained by expressing the standard error as a percentage of the estimate to which it refers. The RSE is a useful measure in that it provides an immediate indication of the percentage errors likely to have occurred due to the effects of random sampling, and this avoids the need to refer also to the size of the estimate. Selected data item RSEs for Australia are shown in the table overleaf. Detailed relative standard errors can be made available on request.
4 To illustrate, the estimated total of gas purchases for Transport, postal and warehousing in 2008-09 was $35m. The RSE of this estimate is shown as 9.4%, giving a standard error of approximately $3.3m. Therefore, there are two chances in three that, if all units had been included in the survey, a figure in the range of $31.7m to $38.3m would have been obtained, and nineteen chances in twenty (i.e. a confidence interval of 95%) that the figure would have been within the range of $28.4m to $41.6m.
5 When referring to Standard Errors of similar magnitudes, smaller estimates have higher RSEs. Percentage contributions when expressed as proportions are inherently smaller than 1, the size of the RSE may be a misleading indicator of the reliability of the estimates, particularly where the proportion is small.
Relative Standard errors for key aggregates
Quantity of electricity purchased
Quantity of natural gas purchased
Value of electricity purchased
Value of natural gas purchased
|Forestry and fishing |
|Electricity, gas and waste services |
|Wholesale trade |
|Retail trade |
|Accommodation and food services |
|Transport, postal and warehousing |
|Information media and telecommunications |
|Auxiliary finance and insurance services |
|Rental, hiring and real estate services |
|Professional, technical and scientific services |
|Administrative and support services |
|Public order, safety and regulatory services |
|Education and training (excluding government) |
|Health care and social assistance (excluding government) |
|Arts and recreation services |
|Other services |
Error other than that due to sampling may occur in any type of collection, whether a full census or a sample, and is referred to as non-sampling error. All data presented in this publication are subject to non-sampling error. It can arise from inadequacies in available sources from which the population frame was compiled, imperfections in reporting by providers, errors made in collection such as in recording and coding data and errors made in processing data. It also occurs when information cannot be obtained from all businesses selected. The imprecision due to non-sampling variability cannot be quantified and should not be confused with sampling variability, which is measured by the standard error.
Although it is not possible to quantify non-sampling error, every effort was made to reduce it to a minimum. Collection forms were designed to be easy to complete and assist businesses to report accurately. Efficient and effective operating procedures and systems were used to compile the statistics. The ABS compared data from different ABS (and non-ABS) sources relating to the one industry, to ensure consistency and coherence.
Differences in accounting policy and practices across businesses and industries can lead to some inconsistencies in the data used to compile the estimates. Although much of the accounting process is subject to standards, there remains a great deal of flexibility available to individual businesses in the accounting policies and practices that they adopt.
The above limitations are not meant to imply that analysis based on these data should be avoided, only that the limitations should be borne in mind when interpreting the data presented in this publication. This publication presents a wide range of data that can be used to analyse business and industry performance. It is important that any analysis be based upon the range of data presented rather than focusing on one variable.
In the 2008-09 survey of energy, water and environment, there was an 88.6% response rate from all businesses that were surveyed and found to be operating during the reference period. Data were imputed for the remaining 11.4% of operating businesses. This imputation contributed 7.8% to the estimate of electricity purchases for the Australian all industries total.
This section discusses the comparability of estimates with other ABS sources.
Comparison with other ABS statistics
A brief discussion is presented below, of the comparability of data in this publication with those in other ABS publications that contain (a) information about energy, water and environmental management and (b) counts of businesses.
Energy, water and environment
The energy consumption figures presented in this publication may not be directly comparable with energy consumption statistics appearing in other publications, for the following reasons:
- The electricity and natural gas consumption figures presented in this publication represent the cost and quantity of electricity and natural gas purchased by businesses for their own consumption. These figures do not reflect energy consumed which is not directly purchased by the business (as described in the following).
- For other fuel types, the energy consumption figures presented represent the cost and quantity of energy used by businesses. These figures exclude the value and quantity of energy produced and consumed in the intermediate steps of a business’s production process. For example, when a business purchases black coal to produce coke, and then uses the coke to produce another product, the value and quantity of the intermediate fuel product (coke) is not reflected in the energy consumption figures for that particular business.
- Energy end-use (final consumption) covers deliveries of commodities to consumers for activities that are not fuel conversion or transformation activities. Other publications may compile estimates on this basis, such as Energy Statistics Australia, 2001-02, (4649.0.55.001). By contrast, the figures presented in this publication include commodities which are converted into other fuel types or products.
- Amounts of electricity and natural gas purchased may not equal total amounts used. Electricity and natural gas purchased may include electricity and natural gas consumed by another business through a rent or leasing arrangement. It excludes electricity and natural gas consumed but not paid for by the business (e.g. invoiced to another business through a rent or leasing arrangement, or self-generated/self-sourced and not purchased from a provider).
Estimates of the number of businesses operating in Australia can be derived from a number of sources within the ABS. They may relate to a particular point in time or may be presented as an average annual figure. However these estimates will not always show the same results. Variations will occur because of differing data sources, differing scope and coverage definitions between surveys, as well as variations due to sampling and non-sampling error. More information about business counts can be found in the ABS information paper A Statistical View of Counts of Businesses in Australia
(cat. no. 8162.0).
The Energy, Water and Environment Survey was not designed to provide high quality estimates of numbers of businesses for any of the output classifications (for example, employment size or industry) and the number of businesses in this publication are only included to provide contextual information for the user. A more robust source of counts of Australian businesses is available from Counts of Australian Businesses, including Entries and Exits, Jun 2007 to Jun 2009 (cat. no. 8165.0), which was released in October 2010.
This page last updated 17 November 2010