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1 This publication contains quarterly estimates of job vacancies based on information obtained from a sample survey of employers.
CONCEPTS, SOURCES AND METHODS
2 Descriptions of the underlying concepts of Australia's job vacancies statistics, and the sources and methods used in compiling these estimates, are presented in Labour Statistics: Concepts, Sources and Methods, 2001 (cat. no. 6102.0) which is available on the ABS website (About Statistics - Concepts and Classifications).
SCOPE AND COVERAGE
3 All job vacancies (as defined in the Glossary) for wage and salary earners are represented in the Job Vacancies Survey (JVS), except those:
4 The sample for the Job Vacancies Survey, like most Australian Bureau of Statistics (ABS) business surveys, is selected from the ABS Business Register which is primarily based on registrations to the Australian Taxation Office's (ATO) Pay As You Go Withholding (PAYGW) scheme (and prior to 1 June 2000 the Group Employer (GE) scheme). The population is updated quarterly to take account of:
5 The estimates include an allowance for the time it takes newly registered businesses to get on to the survey population.
6 Businesses which have ceased employing are identified when the ATO cancels their PAYGW registration. In addition, businesses which did not remit under the PAYGW scheme for the previous five quarters are removed from the frame.
7 A sample of approximately 4,800 employers is selected from the ABS Business Register to ensure adequate state and industry representation. The sample is updated each quarter to reflect changes in the ABS Business Register. These changes arise from the emergence of new businesses, takeovers and mergers, changes to industry classification, changes in the number of employees, and businesses which have ceased operations. Such updating of the register can contribute to changes in the estimates of job vacancies.
8 The statistical unit for the survey comprises all the activities of an employer in a particular state or territory based on the Australian Business Number (ABN) unit or Type of Activity Unit (TAU) (see paragraphs 11 and 15). Each statistical unit is classified to an industry which reflects the predominant activity of the business. The statistical units are stratified by state, sector, industry division and employment size, and within each stratum, statistical units are selected with equal probability.
STATISTICAL UNITS DEFINED ON THE ABS BUSINESS REGISTER
9 The ABS uses an economic statistics units model on the ABS Business Register to describe the characteristics of businesses, and the structural relationships between related businesses. The units model is also used to break groups of related businesses into relatively homogeneous components that can provide data to the ABS.
10 In mid-2002, to better use the information available as a result of The New Tax System, the ABS changed its economic statistics units model. The new units model allocates businesses to one of two sub-populations. The vast majority of businesses are in what is called the ATO Maintained Population, while the remaining businesses are in the ABS Maintained Population. Together, these two sub-populations make up the ABS Business Register population.
ATO maintained population
11 Most businesses and organisations in Australia need to obtain an Australian Business Number, and are then included on the ATO Australian Business Register. Most of these businesses have simple structures; therefore the unit registered for an ABN will satisfy ABS statistical requirements. For these businesses, the ABS has aligned its statistical units structure with the ABN unit. The businesses with simple structures constitute the ATO Maintained Population, and the ABN unit will be used as the economic statistics unit for all economic collections.
ABS maintained population
12 For the population of businesses where the ABN unit is not suitable for ABS statistical requirements, the ABS maintains its own units structure through direct contact with the business. These businesses constitute the ABS Maintained Population. This population consists typically of large, complex and diverse businesses. The new statistical units model described below has been introduced to cover such businesses.
13 Enterprise Group: This is a unit covering all the operations in Australia of one or more legal entities under common ownership and/or control. It covers all the operations in Australia of legal entities which are related in terms of the current Corporations Law (as amended by the Corporations Legislation Amendment Act 1991), including legal entities such as companies, trusts, and partnerships. Majority ownership is not required for control to be exercised.
14 Enterprise: The enterprise is an institutional unit comprising (i) a single legal entity or business entity, or (ii) more than one legal entity or business entity within the same Enterprise Group and in the same institutional sub-sector (i.e. they are all classified to a single Standard Institutional Sector Classification of Australia sub-sector).
15 Type of Activity Unit: The TAU comprises one or more business entities, sub-entities or branches of a business entity within an Enterprise Group that can report production and employment data for similar economic activities. When a minimum set of data items is available, a TAU is created which covers all the operations within an industry subdivision (and the TAU is classified to the relevant subdivision of the Australian and New Zealand Standard Industrial Classification [ANZSIC]). Where a business cannot supply adequate data for each industry, a TAU is formed which contains activity in more than one industry subdivision.
16 For more information on the impacts of the introduction of the new economic statistics units model, refer to Information Paper: Improvements in ABS Economic Statistics [Arising from the New Tax System] (cat. no. 1372.0).
COMPARABILITY OF SERIES
17 Job vacancies series in this publication were introduced with the November 1983 issue of the Job Vacancies and Overtime survey publication. Estimates contained in this publication are not strictly comparable with those obtained prior to November 1983.
18 Between August and November 1999 a number of improvements were made to operational procedures, in conjunction with the discontinuation of the overtime component of the survey. These improvements resulted in an increase in job vacancy estimates for the private sector. There was negligible change to public sector estimates. Consequently, private sector estimates prior to November 1999 were adjusted to provide a comparable and compatible time series.
19 To account for the New Tax System changes described in paragraphs 9 to 16, the historical series from May 2002 back to November 1983 have been revised to make the time series of estimates as continuous as possible.
20 From November 2003 number of employees is no longer collected in the Job Vacancy Survey. Consequentially job vacancy rates (see Glossary) are no longer presented in this publication. A job vacancy rate series, based on estimates of the number of employees from the Labour Force Survey, is available on request.
EFFECTS OF ROUNDING
21 Where figures have been rounded, discrepancies may occur between sums of the component items and totals. Percentages in this publication are calculated using unrounded numbers and consequently could differ from percentages that are calculated from the published rounded statistics.
22 Seasonal adjustment is a means of removing the estimated effects of normal seasonal variation from the series so that the effects of other influences can be more clearly recognised. Seasonal adjustment does not aim to remove the irregular or non-seasonal influences which may be present in any particular series. Influences that are volatile or unsystematic can still make it difficult to interpret the movement of the series even after adjustment for seasonal variation. This means that quarter-to-quarter movements of seasonally adjusted estimates may not be reliable indicators of trend behaviour.
23 The quarterly series have been seasonally adjusted from February quarter 1984 and the historical series can be made available on request. The seasonal factors are reviewed annually to take account of each additional year's original data. The most recent review, using original estimates to August 2003, took place in time for inclusion in the November 2003 estimates.
24 Details about the method of seasonal adjustment of these series are available on request.
25 Seasonally adjusted estimates can be smoothed to reduce the impact of irregular or non-seasonal influences. Smoothed seasonally adjusted series are called trend estimates.
26 The ABS considers that trend estimates provide a more reliable guide to the underlying direction of the data, and are more suitable than either the seasonally adjusted or original estimates for most business decisions and policy advice.
27 Trend estimates, obtained by dampening out the irregular component from the seasonally adjusted series, are calculated using a centred 7-term Henderson moving average of the seasonally adjusted series. Estimates for the three most recent quarters cannot be calculated using this centred average method; instead an asymmetric average is used. This can lead to revisions in the trend estimates for the last three quarters when data become available for later quarters. Revisions of trend estimates will also occur with revisions to the original data and re-estimation of seasonal adjustment factors.
28 If a series is highly volatile then the trend estimates will be subject to greater revision for the latest few quarters as new data become available. However, it is important to note that this does not make the trend series inferior to the seasonally adjusted or original series.
29 For more information, refer to Information Paper: A Guide to Interpreting Time Series-Monitoring Trends (cat. no. 1349.0) which is available free of charge from the ABS web site.
30 Two feature articles which have appeared in the ABS monthly publication Australian Economic Indicators (cat. no. 1350.0) may also be of interest:
31 Users may also wish to refer to the following publications which are available from ABS Bookshops:
32 Current publications and other products released by the ABS are listed in the Catalogue of Publications and Products (cat. no. 1101.0). The Catalogue is available from any ABS office or the ABS web site (Products and Services). The ABS also issues a daily Release Advice on the web site (Information on Releases) which details products to be released in the week ahead.
ABS DATA AVAILABLE ON REQUEST
33 As well as the statistics included in this and related publications, the ABS may have other relevant data available on request. Inquiries should be made to National Information and Referral Service on 1300 135 070 or to Manpreet Singh on Perth (08) 9360 5304.
TECHNICAL NOTE - DATA QUALITY
RELIABILITY OF ESTIMATES
1 As the estimates in this publication are based on information relating to a sample of employers rather than a full enumeration, they are subject to sampling variability. That is, they may differ from the estimates that would have been produced if the information had been obtained from all employers. This 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. Such inaccuracy is referred to as non-sampling error and may occur in any enumeration whether it be a full count or sample. Efforts have been made to reduce non-sampling error by careful design of questionnaires, detailed checking of returns and quality control of processing.
2 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 which indicates the degree to which an estimate may vary from the value which would have been obtained from a full enumeration (the ‘true value’). There are about two chances in three that a sample estimate differs from the true value by less than one standard error, and about 19 chances in 20 that the difference will be less than two standard errors.
3 An example of the use of a standard error on levels is as follows. If the estimated number of job vacancies was 25,000 with a standard error of 2,500, then there would be about two chances in three that a full enumeration would have given an estimate in the range 22,500 to 27,500 and about 19 chances in 20 that it would be in the range 20,000 to 30,000.
4 An example of the use of a standard error for a quarterly change estimate is as follows. If the estimated standard error for a quarterly change estimate of job vacancies was 1,000 and the quarterly change estimate between two quarters was 4,500, then there would be about two chances in three that a full enumeration would have given a quarterly change estimate in the range +3,500 to +5,500 and about 19 chances in 20 that it would be in the range +2,500 to +6,500.
5 Quarterly movements in estimates of job vacancies are considered to be statistically significant where they exceed two standard errors.
6 Another measure of the sampling error is the relative standard error, which is obtained by expressing the standard error as a percentage of the estimate. Level estimates with a relative standard error of 25% and 50%, denoted by a single asterisk in this publication, are subject to sampling variability generally considered to be too high for most practical purposes and should be used with caution. Level estimates with a relative standard error of 50% or more, denoted by a double asterisk, are considered to be too unreliable for general use.
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