SURVEY METHODOLOGY


SCOPE AND COVERAGE
SAMPLE DESIGN
WEIGHTING AND ESTIMATION
RELIABILITY OF THE ESTIMATES
MORE INFORMATION


SCOPE AND COVERAGE

The May 2012 Survey of Employee Earnings and Hours (EEH) covers all employing organisations in Australia (public and private sectors) except:

• businesses primarily engaged in agriculture, forestry and fishing (ANZSIC Division A);
• private households employing staff; and
• foreign embassies, consulates, etc.

The employees of employers covered in the survey are in scope if they received pay for the reference period, except:

• members of the Australian permanent defence forces;
• employees based outside Australia; and
• employees on workers’ compensation who are not paid through the payroll.

SAMPLE DESIGN

The survey uses a two-stage sample selection approach. The first stage involves selecting a probability sample of employer units from the ABS Business Register. The statistical unit for the first stage comprises all activities of an employer in a particular state or territory based on the Australian Business Number (ABN) unit or Type of Activity Unit (TAU). A sample of approximately 8,400 employer (selection) units was selected to ensure adequate industry and state/territory representation.

In the second stage, businesses selected in the first stage are asked to select a random sample of employees from their payrolls using instructions provided by the ABS. Data for approximately 55,000 employees contributed to the results in this CURF.
WEIGHTING AND ESTIMATION

Records are weighted in two stages, reflecting the two-stage sample design. In the first stage, number-raised estimation is used to estimate the number of employees in each employer unit in the stratum. In the second stage, number-raised estimation is again used to estimate the total number of employer units, resulting in an estimate of employees. The final weight for each selected employee is a combination of the 'employer unit' weight and the 'employee' weight.
RELIABILITY OF THE ESTIMATES

As the information on the CURF relates to a sample of employers and employees, rather than a full enumeration, estimates based on the information 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 employers and employees. The difference, called sampling error, should not be confused with inaccuracy that may occur because of imperfections in reporting by respondents or in processing by the ABS. Collectively, these are called non-sampling errors.


Sampling error

The sampling error associated with any estimate can be estimated from the sample results. One measure of sampling error is given by the standard error (SE), which indicates the degree to which an estimate may vary from the value that would have been obtained from a full enumeration (the 'true value'). There are about two chances in three (67%) that a sample estimate differs from the true value by less than one SE, and about 19 chances in 20 (95%) that the difference will be less than two SEs.

Another measure of the sampling error is the relative standard error (RSE), which is obtained by expressing the SE as a percentage of the estimate.

Further information on sampling error is provided in the Technical Note of Employee Earnings and Hours, Australia, May 2012 (cat. no. 6306.0).


Non-sampling error

Non-sampling error arises from inaccuracies in collecting, recording and processing the data. These inaccuracies may occur in any enumeration, whether it be a full count or a sample. Efforts have been made to reduce non-sampling error by careful design of questionnaires, detailed checking of returns and quality control of processing.

MORE INFORMATION

Further information on the survey methodology can be found in:

• Employee Earnings and Hours, Australia, May 2012 (cat. no. 6306.0); and
• Labour Statistics: Concepts, Sources and Methods (cat. no. 6102.0.55.001).