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SURVEY METHODOLOGY

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RELIABILITY OF ESTIMATES

Two types of error are possible in an estimate based on a sample survey: sampling error and non-sampling error.

Sampling error occurs because a sample, rather than the entire population, is surveyed. One measure of the likely difference resulting from not including all dwellings in the survey is given by the standard error. There are about two chances in three (67%) that a sample estimate will differ by less than one standard error from the figure that would have been obtained if all dwellings had been included in the survey, and about nineteen chances in twenty (95%) that the difference will be less than two standard errors.

Standard errors for cross-sectional (point-in-time) estimates from the CURF may be calculated by using the spreadsheet contained in Labour Force Survey Standard Errors, Data Cube (cat. no. 6298.0.55.001). which is based on the standard error models detailed in Labour Force Survey Standard Errors, 2005 (cat. no. 6298.0). The models do not provide standard errors for estimates resulting from longitudinal analysis, but the cross-sectional standard errors may be used as an approximate indication.

Furthermore, these models don't account for the smaller sample and population exclusions of the data items collected in the supplementary surveys. The standard errors published in the supplementary publications can be used as a guide to the reliability of estimates derived from those items, refer to Survey Methodology for links to the supplementary survey publications.

Non-sampling error arises from inaccuracies in collecting, recording and processing the data. Every effort is made to minimise reporting error by the careful design of questionnaires, intensive training and supervision of interviewers, and efficient data processing procedures. Non-sampling error also arises because information cannot be obtained from all persons selected in the survey. The Labour Force Survey receives a high level of co-operation from individuals in selected dwellings, with the average response rate over the last year being 96%. Similar levels of co-operation are also observed in the supplementary surveys.


Related Information

Labour Force, Australia: Explanatory Notes - 25. Reliability of Estimates (cat. no. 6202.0)
Labour Force, Australia: Standard Errors (cat. no. 6202.0)
Labour Force, Australia, Detailed, Quarterly: Standard Errors (cat. no. 6291.0.55.003)
Labour Statistics: Concepts, Sources and Methods: 20. Labour Force Survey - 20.34 Reliability of the Estimates (cat. no. 6102.0.55.001)
Labour Force Survey Standard Errors, 2005 (cat. no. 6298.0)
Labour Force Survey Standard Errors, Data Cube (cat. no. 6298.0.55.001)

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