Microdata: Pregnancy and Employment Transitions, Australia

Enables detailed analysis of employment for mothers and partners during pregnancy and after birth

Introduction

This product provides information about the release of microdata from the November 2011 Pregnancy and Employment Transitions Survey including details about the survey methodology and how to use the Microdata. Also provided are the data item list, a glossary and information on the conditions of use and the quality of the microdata.

Microdata are the most detailed information available from a survey and are generally the responses to individual questions on the questionnaire or data derived from two or more questions and are released with the approval of the Australian Statistician.

Available products

The following microdata product is available from this survey:

  • Detailed Microdata via DataLab.

Further information about these services, and other information to assist users in understanding and accessing Microdata in general, is available from the Microdata Entry Page on the ABS web site.

Before you apply for access, users should read and familiarise themselves with the information contained in this product and the Responsible Use of ABS Microdata, User Guide.

To apply for access click here.

Further information

Further information about the survey and the microdata products can be found in this product:

  • A detailed list of data items for the Microdata are available in the Data downloads section;
  • The Abbreviations and Glossary relating to these products can be found in the left navigation menu.

Data available on request

Data obtained in the survey but not contained in the Microdata may be available from the ABS, on request, as statistics in tabulated form.

Subject to confidentiality and sampling variability constraints, special tabulations can be produced incorporating data items, populations and geographic areas selected to meet individual requirements. These are available on request, on a fee for service basis. For more information, contact the ABS by visiting www.abs.gov.au/about/contact-us.

Survey methodology

Scope and coverage

The scope of the Labour Force Survey (LFS) is restricted to persons aged 15 years and over and excludes the following people:

  • members of the permanent defence forces;
  • certain diplomatic personnel of overseas governments, customarily excluded from the Census and estimated populations; and
  • overseas residents in Australia; and members of non-Australian defence forces (and their dependants).

Students at boarding schools, patients in hospitals, residents of homes (e.g. retirement homes, homes for people with disabilities), and inmates of prisons are excluded from all supplementary surveys.

This supplementary survey was conducted in both urban and rural areas in all states and territories, but excluded persons living in Aboriginal and Torres Strait Islander communities in very remote parts of Australia.

Only women aged 15 years and over who had given birth to a child less than two years ago and were living with that child were included in the survey. The survey excluded:

  • women who were members of the Australian permanent defence forces;
  • women living in non-private dwellings;
  • visitors to private dwellings; and
  • all males.

In addition, for those women whose partner at the time of interview was not in scope of the survey (e.g. the partner was in the permanent defence forces), the details of the partner's job at November 2011 was not collected. For these partners, job details at November 2011 were classified as not applicable.

In the LFS, coverage rules are applied which aim to ensure that each person is associated with only one dwelling and hence has only one chance of selection in the survey. See Labour Force, Australia (cat. no. 6202.0) for more details.

Survey design

Supplementary surveys are not conducted on the full LFS sample. Since 1994 the sample for supplementary surveys has been restricted to no more than seven-eighths of the LFS sample. The sample for PaETS is a subsample of 36,604 private dwelling households and special dwelling units included in the ABS Monthly LFS in November 2011. The final sample on which estimates are based is composed of 1,351 birth mothers aged 15 years and over, usually resident in these private and special dwellings in Australia, with at least one child less than two years of age living with them at the time of interview. In cases where women had more than one child under the age of two, data was collected in respect of the employment transitions of women around the birth of their most recent child (i.e. the youngest child).

Data collection methodology

Data were collected by trained interviewers, who conducted computer-assisted personal and telephone interviews at selected dwellings throughout Australia. These interviews were primarily conducted over two weeks in November 2011, with any follow up activity necessary undertaken during the following two weeks.

The publication, Labour Force, Australia (cat. no. 6202.0), contains information about survey design, sample redesign, scope, coverage and population benchmarks relevant to the monthly LFS, which also applies to the supplementary surveys. It also contains definitions of demographic and labour force characteristics, and information about interviewing which are relevant to both the monthly LFS and supplementary surveys.

Weighting, benchmarking and estimation

Weighting

Weighting is the process of adjusting results from a sample survey to infer results for the total population. To do this, a 'weight' is allocated to each sample unit. The weight is a value which indicates how many population units are represented by the sample unit.

The first step in calculating weights for each person is to assign an initial weight, which is equal to the inverse of the probability of being selected in the survey. For example, if the probability of a person being selected in the survey was 1 in 300, then the person would have an initial weight of 300 (that is, they represent 300 people).

Separate weights were calculated for LFS and Pregnancy and Employment Transitions Survey samples (as some units were in scope for LFS but not for the Pregnancy and Employment Transitions Survey). The LFS weighting method ensures that LFS estimates conform to the benchmark distribution of the population by age, sex and geographic area, and also LFS region by sex (two sets of benchmarks). Weights are allocated to each sample respondent according to their state/territory of selection, state/territory of usual residence, part of state of usual residence, age group and sex.

Benchmarking

The weights were calibrated to align with independent estimates of the population, referred to as benchmarks, in designated categories of sex by age by area of usual residence. Weights calibrated against population benchmarks ensure that the survey estimates conform to the independently estimated distribution of the population rather than to the distribution within the sample itself. Calibration to population benchmarks helps to compensate for over or under-enumeration of particular categories of persons which may occur due to either the random nature of sampling or non-response.

The Pregnancy and Employment Transitions Survey is benchmarked to LFS estimates for the following variables: state or territory of usual residence, part of state or territory of usual residence, sex, age group, social marital status.

Benchmarking to LFS estimates accounts for the one-eighth of the sample where the Pregnancy and Employment Transitions Survey is not conducted and for non-respondents to the Pregnancy and Employment Transitions Survey. The Pregnancy and Employment Transitions Survey weighting excludes all residents in institutions, boarding schools, and very remote areas because the sample scope excludes these people.

Due to differences in scope and sample size between this supplementary survey and that of the LFS, the estimation procedure may lead to some small variations between labour force estimates from this survey and those from the LFS.

Estimation

Survey estimates of counts of persons are obtained by summing the weights of persons with the characteristic of interest. Estimates of non-person counts (e.g. days away from work) are obtained by multiplying the characteristic of interest with the weight of the reporting person and aggregating.

Comparison with 2005 Microdata

The ABS conducted the first Pregnancy and Employment Transitions Survey in November 2005. November 2011 was the second time this survey has been conducted. Results from most recent survey, Pregnancy and Employment Transitions, Australia (cat. no. 4913.0) were released in November 2012.

Care should be taken when comparing results from the November 2011 Pregnancy and Employment Transitions Survey to the November 2005 Pregnancy and Employment Transitions Survey.

The November 2011 Pregnancy and Employment Transitions Survey was redeveloped to better capture information on:

  • job details and types of leave taken while women were pregnant;
  • job details about women's first job started or returned to since the birth of the child;
  • women with a child under 2 years, job at November 2011;
  • partner's job details and types of leave taken while women were pregnant;
  • job details about partner's first job started or returned to since the birth of the child; and
  • partner's job details at November 2011.

Information on key changes made to the Pregnancy and Employment Transitions Survey can be found in the Explanatory Notes of the publication, Pregnancy and Employment Transitions, Australia (cat. no. 4913.0).

As a result of the redevelopment, the data items on the 2011 Microdata will not align with the data items on the 2005 Microdata.

Reliability of estimates

Seasonal factors

Estimates are based on information collected in the survey month, and, due to seasonal factors, they may not be representative of other months of the year.

More information

File structure

Weights and estimation

As the survey was conducted on a sample of households in Australia, it is important to take account of the method of sample selection when deriving estimates from the Microdata. This is particularly important as a person's chance of selection in the survey varied depending on the state or territory in which they lived.

Each person record contains a weight which for the Pregnancy and Employment Transitions Survey is called FINPRSWT. The weight indicates the number of people in the civilian population represented by that person.

The Pregnancy and Employment Transitions Survey weight, FINPRSWT, appears on all 1,351 records. The estimates in the Pregnancy and Employment Transitions Survey publication are based on these records, that is women with a child under the age of two years during November 2011. Therefore when using FINPRSWT, to match the published Pregnancy and Employment Transitions Survey total estimate, the filter POP1=1 must be used.

Where estimates are derived from the Microdata, it is essential that they are calculated by adding the weights of persons in each category and not just by counting the number in each category. If each person's 'weight' is ignored, then no account would be taken of a person's chance of selection or of different response rates across population groups, and the resulting estimates could be significantly biased and would only represent distributions within the actual selected sample and not the population of interest. The application of weights will ensure that the subsequent estimates conform to an independently estimated distribution of the population by age and sex, rather than to the age and sex distribution within the sample itself.

For further information see the Explanatory Notes in the publication Pregnancy and Employment Transitions, Australia (cat. no. 4913.0).

Standard errors

Standard errors for each estimate produced from this Microdata can be calculated using the replicate weights provided on the file.

Each person record contains a set of 30 replicate weights. Replicate weights applicable to the Pregnancy and Employment Transitions Survey data items, contain the prefix 'WPX02'. By using these weights, it is possible to calculate standard errors for weighted estimates produced from the microdata. This method is known as the 30 group Jackknife variance estimator. For data items that are only applicable to the Pregnancy and Employment Transitions Survey, refer to Data Item List.

Under the Jackknife method of replicate weighting, weights were derived as follows:

  • 30 replicate groups were formed with each group formed to mirror the overall sample (where units from a collection district all belong to the same replicate group and a unit can belong to only one replicate group)
  • one replicate group was dropped from the file and then the remaining records were weighted in the same manner as for the full sample
  • records in that group that were dropped received a weight of zero.

This process was repeated for each replicate group (i.e. a total of 30 times). Ultimately each record had 30 replicate weights attached to it with one of these being the zero weight.

Replicate weights enable variances of estimates to be calculated relatively simply. They also enable unit records analyses such as chi-square and logistic regression to be conducted which take into account the sample design. Replicate weights for any variable of interest can be calculated from the 30 replicate groups, giving 30 replicate estimates. The distribution of this set of replicate estimates, in conjunction with the full sample estimate (based on the general weight) is then used to approximate the variance of the full sample.

To obtain the standard error of a weighted estimate y, the same estimate is calculated using each of the 30 replicate weights. The variability between these replicate estimates (denoting y(g) for group number g) is used to measure the standard error of the original weighted estimate y using the formula:

\(SE(y) = \sqrt {(29/30) \sum \limits^{30} _{g=1} (y _{(g)} - y)^2 }\)

Where:

\(g\) = the replicate groups

\(y_{(g)}\) = the weighted estimate, having applied the weights for replicate group 'g'

\(y\) = the weighted estimate from the full sample.

The 30 group Jackknife method can be applied not just to estimates of population total, but also where the estimate y is a function of estimates of population total, such as a proportion, difference or ratio. For more information on the 30 group Jackknife method of SE estimation, see Research Paper: Weighting and Standard Error Estimation for ABS Household Surveys (Methodology Advisory Committee), July 1999 (cat. no. 1352.0.55.029).

Use of the 30 group Jackknife method for complex estimates, such as regression parameters from a statistical model, is not straightforward and may not be appropriate. The method as described does not apply to investigations where survey weights are not used, such as in unweighted statistical modelling.

The following table has been provided to enable Microdata users to check some of the relative standard errors they have produced.

Women with child under 2 years - by selected characteristics
 WomenRelative Standard Error
'000%
Age of women (years)  
 15 - 2459.410.9
 25 - 29130.35.3
 30 - 34175.84.7
 35 - 39112.95.8
 40 and over44.910.3
Social marital status  
 Married459.63.1
 Not married63.79.2
Country of birth and period of arrival  
 Born in Australia385.63.5
 Born overseas137.75.0
  Arrived before 200154.910.2
  Arrived 2001 to the date of interview82.85.2
Total523.33.2

Not applicable categories

Many data items included in the Microdata include a 'Not applicable' category. The classification value of the 'Not applicable' category, where relevant, is shown in the relevant data item lists available in the Data downloads section.

Using the Microdata

About the Microdata

The data included in the Pregnancy and Employment Transition Survey, November 2011 Detailed Microdata are released under the provisions of the Census and Statistics Act 1905. This legislation allows the Australian Statistician to release unit record data, or microdata, provided this is done “in a manner that is not likely to enable the identification of a particular person or organisation to which it relates.”

The ABS ensures the confidentiality of the data by:

  • removing name, address and any other information that might uniquely identify any individual
  • changing a small number of values - particularly unusual values - and removing very unusual records
  • controlling the detail available for all records on the Detailed Microdata
  • excluding some data items that were collected
  • controlling the modes of access to restrict access to more detailed data
  • placing restrictions on how the data are used, supported by both information in the Responsible Use of ABS Microdata, User Guide,  the undertaking signed by the head of each organisation and the terms and conditions signed by each user.

As a result, data on the Detailed Microdata will not exactly match other previously published estimates. Any changes to the distribution of values are not significant and the statistical validity of aggregate data is not affected.

Identifiers

Each person has a unique random identifier - ABSPID.

Detailed Microdata file contents

The Pregnancy and Employment Transitions Survey November 2011 Detailed Microdata can be accessed in DataLab and is available in SAS, SPSS and STATA formats. Detailed Microdata comprises the following files:

Data files

Information files

Data item list

The Pregnancy and Employment Transitions Survey comprised a questionnaire containing 4 modules and approximately 170 questions.

All data items are available for the Pregnancy and Employment Transitions Survey sample. Users intending to purchase the Microdata should ensure that the data they require, and the level of detail they need, are available in this product.

The Detailed Microdata file contains 166 data items. The data items list for the Detailed Microdata, including relevant population and classification details, can be found in the Excel spreadsheet available from the Data downloads section. The data items are sorted by like items in 10 worksheets contained in the spreadsheet.

These worksheets are named as follows:

  • Populations;
  • Record Identifiers & Weights;
  • Demographic;
  • Income;
  • Womens job while pregnant;
  • Partners job during pregnancy;
  • Womens first job after birth;
  • Partners first job after birth;
  • Womens current job; and
  • Partners current job.

The Pregnancy and Employment Transitions Survey Detailed Microdata contain 1,351 confidentialised respondent records from the survey. Subject to the limitations of the sample size and the data classifications used, it is possible to interrogate the Microdata, produce tabulations and undertake statistical analyses to individual specifications.

Data downloads

Data item list

Previous releases

 TableBuilder data seriesMicrodataDownloadDataLab
Pregnancy and Employment Transitions, 2005  Detailed microdata

Glossary

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Abbreviations

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Previous catalogue number

This release previously used catalogue number 4913.0.55.001.

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