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TECHNICAL NOTE 1 METHODOLOGY
CONTRIBUTION OF THE STATISTICAL UNITS TO THE ESTIMATES
5 The following paragraphs outline the way in which categories of statistical units contribute to the estimates of financial and economic variables presented in this publication.
6 All units in the ABSMP (i.e. TAUs) were eligible to be selected for direct collection. Direct collection of data from these units is necessary because:
7 All units on the ABSBR not classified as TAUs were ABN units from the ATOMP.
8 An indication of the importance of these populations can be gained from their contribution to the national estimate of sales and service income for Total selected industries. The following table shows their proportional contributions to sales and service income.
9 In order to decrease the statistical reporting load placed on providers while maintaining the range and quality of information available to users of statistical data, the strategy for this survey was to adopt the use of directly collected data from a smaller sample of businesses, in combination with information sourced from the ATO. The frame (from which the direct collect sample was selected) was stratified using information held on the ABSBR. Businesses eligible for selection in the direct collect sample were then selected from the frame using stratified random sampling techniques.
10 Businesses were selected to participate in the survey (the direct collect sample) only if their turnover exceeded a threshold level or the business was identified as being an employing business (based on ATO information) as at the end of the reference period. Turnover thresholds were set for each ANZSIC class so that the contribution of surveyed businesses accounted for 97.5% of total industry class turnover as determined by BAS data.
11 Businesses which met neither of these criteria are referred to as 'micro non-employing businesses'. These businesses were not eligible for selection in the sample. For these units, BAS data were obtained and annualised, then added to the directly collected estimates to produce the statistics in this publication. The total estimated value of annual turnover of micro non-employing businesses in Total selected industries during the 2007-08 reference year, as determined by BAS data, was $53.2b.
12 The 2007-08 survey continues to use generalised regression estimation, first introduced in the 2006-07 survey. This estimation method enables maximum use of observed linear relationships between data directly collected from businesses in the survey and auxiliary information. When the auxiliary information is strongly correlated with data items collected in a survey, the generalised regression estimation methodology will improve the accuracy of the estimates. The auxiliary variables used in this survey were turnover and wages sourced from BAS data.
13 The following diagram illustrates the ways in which Australian businesses contribute to the estimates in this publication.
14 For the purpose of compiling the estimates in this publication, data for businesses as recorded on the ABSBR contribute via one of three categories (or 'streams') in accordance with significance and collection-related characteristics.
Completely enumerated (CE) stream:
15 The CE stream consists of directly collected survey data for those units recorded on the ABSBR as having employment greater than 300, plus additional 'significant' units in the ABSMP and units significant to small state estimates.
Generalised regression (GREG) estimation stream:
16 The GREG stream comprises directly collected data for those sampled units which are not in the CE stream and have turnover, in aggregate, above the bottom 2.5 percentile of BAS sales for that industry. The accuracy of the estimates produced from this data is then improved by using wages and turnover data sourced from businesses' BAS data.
Business Activity Statement (BAS) stream:
17 The BAS stream comprises data for those businesses in the ATOMP whose turnover, in aggregate, is below the bottom 2.5 percentile of BAS sales for that ANZSIC subdivision.
18 Estimates for each of the selected industries were produced by aggregating the contributing data streams.
STATE AND TERRITORY ESTIMATES
19 A small component of the sample survey was not specifically designed to produce state estimates. For these units state data was apportioned utilising BAS data obtained from the ATO. For the remainder of sampled units, a question on the survey form requesting state break ups of employment, wages and salaries, and sales and service income was used.
20 Data collected for 2004-05 and 2005-06 (under ANZSIC93) were updated in the 2006-07 issue of this publication to take account of any revisions to the data since they were originally published in the 2005-06 issue. The data so revised were then mapped to ANZSIC06, and further adjusted to incorporate the scope and methodological changes discussed in the notes for the 2006-07 publication. This process is known as 'bridging' and was used to create the key data items presented in table 1.1 for 2004-05 and 2005-06.
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