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UNDERSTANDING MOVEMENTS IN EMPLOYMENT
A person is classified to part-time employment if they usually work less than 35 hours per week, and either did so during the reference week, or were not at work in the reference week.
COMPARABILITY OF DATA BETWEEN SURVEYS
In the Labour Force Survey, one-eighth of the dwellings sampled in the previous month are replaced, in the current month, by a new set of dwellings from the same geographic area. The seven-eighth overlap between the dwellings selected in consecutive months maintains continuity within the population survey sample and enables more reliable measurement of change in the labour force characteristics of the population than would be possible if a new sample was introduced each month.
The matching of respondents who report in consecutive months enables analysis of the transition of individuals between the different labour force status classifications, referred to as the matched sample. The transition counts between the different labour force status classifications from one point in time to the next are commonly referred to as gross flows.
The figures presented in gross flows are presented in original terms only and do not align with published labour force estimates. The gross flows figures are derived from the matched sample between consecutive months, which after taking account of the sample rotation and varying non-response in each month is approximately 80 per cent of the sample.
The section titled Quality of gross flows figures discusses this and other properties of the gross flows figures, which should be kept in mind when using these data for analysis.
USING GROSS FLOWS FIGURES TO ANALYSE MOVEMENTS IN EMPLOYMENT
Gross flows figures can assist in understanding the movements in labour force status. For example, in the March 2009 labour force estimates, the number of employed persons, in trend terms, decreased 5,000 persons; comprised of a decrease in full-time employment of 14,600 persons, that was partly offset by an increase in part-time employment of 9,700 persons. However, in original terms, the number of employed persons decreased 1,500 persons; comprised of a decrease in full-time employment of 123,200 persons and an increase in part-time employment of 121,700 persons.
When attempting to interpret the decrease in full-time employment the following questions arise regarding the population:
Movement between full-time employment and part-time employment
Referring to the following table one can observe, in original terms, the following counts for transitions between full-time employment and part-time employment:
In the matched sample, there were considerably more persons who moved from full-time employment to part-time employment than in the other direction. Therefore, one can observe, from the gross flows figures that a contributing factor to the March 2009 increase in part-time employment was the net transition of persons from full-time employment to part-time employment.
Movement between employment and unemployment
Referring to the following table one can observe, in original terms, the following counts for transitions between employment and unemployment:
Therefore, one can observe from the matched sample, that there were more persons who moved from unemployment to employment than in the other direction.
Movement between employment and persons not in the labour force
Referring to the following table one can observe, in original terms, the following counts for transitions between employment and persons not in the labour force:
Therefore, one can observe from the matched sample, that a proportion of the decrease in employment was due to employed persons moving directly out the labour force.
QUALITY OF GROSS FLOWS FIGURES
Caution should be exercised when analysing these gross flows data. First, as noted above, the figures presented sum to approximately 80 per cent of the population values as the gross flows data are based on the matched sample only.
Second, there is no adjustment applied to account for changes due to seasonal patterns (referred to commonly as seasonal adjustment). The gross flows figures are based on original data. Therefore, residual noise, seasonal patterns and irregular influences in the series may lead to misleading conclusions where there is a strong seasonal pattern. Therefore, gross flows figures need to be interpreted in the context of the seasonal nature of the labour force.
Third, the relative sizes of each transition class are subject to bias due to the matched sample being a non-representative sample.
Bias in the estimates due to non-representative sample
The Labour Force Survey sample selection procedures aim to ensure that the individuals surveyed at each time point are a representative sample of the population, and the survey weighting procedure will largely correct for any imbalances in the sample.
The mobility of the population and non-response, in either or both consecutive surveys, means that about 10 per cent of persons in private dwellings, which are included in the sample in successive months, cannot be matched. The matched sample will tend to under-represent particular types of individuals, for example those who move between houses.
The relative size of the transition classes in the gross flows data will be subject to bias if the labour characteristics of those individuals under-represented differ from characteristics of the remainder. Differences in the labour characteristics of those under-represented appears quite related likely, since, for example, moving house can be related to a transition in labour force status.
Gross flows figures can assist in understanding the movements in labour force estimates. The figures presented in gross flows do not align with published labour force estimates and should only be used to interpret movements in published estimates.
The ABS is investigating alternative methods for producing gross flows data which reduce the potential bias on the figures, therefore reducing some of the quality concerns of gross flows data.
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