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5 The 2007-08 MPHS also excluded:
6 The 2007-08 MPHS was conducted in both urban and rural areas in all states and territories, but excluded people living in very remote parts of Australia. The exclusion of these people is expected to have only a minor impact on any aggregate estimates that are produced for individual states and territories, except the Northern Territory where such people account for around 23% of the population.
7 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. 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 MPHS. It also contains definitions of demographic and labour force characteristics, and information about telephone interviewing relevant to both the monthly LFS and the MPHS.
8 The MPHS is conducted as a supplement to the monthly Labour Force Survey (LFS). One eighth of the LFS sample is rotated out of the survey each month, called the 'outgoing rotation group'. One third of the dwellings in this outgoing rotation group are selected for the MPHS. In each of these dwellings, after the LFS has been fully completed for each person in scope and coverage, a person (usual resident) aged 18 years and over is selected at random (based on a computer algorithm) and asked the additional MPHS questions on Environmental Views and Behaviour in a personal interview. Data are collected using Computer Assisted Interviewing (CAI), whereby responses are recorded directly onto an electronic questionnaire in a notebook computer generally during a telephone interview.
Environmental Views and Behaviour
9 The usual MPHS sample is accumulated over a twelve month period (July 2007 to June 2008). Refer above to paragraph 2 in the Introduction for the final sample size.
WEIGHTING, ESTIMATION AND BENCHMARKING
10 Weighting is the process of adjusting results from a sample survey to infer results for the total in scope 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.
11 The first step in calculating weights for each unit is to assign an initial weight, which is the inverse of the probability of being selected in the survey. The initial weights are then calibrated to align with independent estimates of the population of interest, referred to as 'benchmarks'. Weights are calibrated against population benchmarks to ensure that the survey estimates conform to the independently estimated distribution of the population rather than the distribution within the sample itself.
12 The estimation process for this survey ensures that estimates of persons calibrate exactly to independently produced population totals at broad levels. The known population totals, commonly referred to as 'benchmarks', are produced according to the scope of the survey.
13 Survey estimates are benchmarked to persons within the scope of the survey - for example, the MPHS was benchmarked to the estimated civilian population aged 18 years and over living in private dwellings in each state and territory excluding persons out of scope. Survey estimates of counts of persons are obtained by summing the weights of persons with the characteristics of interest.
INCOME LESS THAN ZERO
14 Some persons reported negative income in the survey. This is possible if they incur losses in their unincorporated business or have negative returns from their investments. Studies of income and expenditure from the Household Expenditure Survey, Australia (cat. no. 6530.0) have shown that such households in the bottom income decile and with negative gross incomes tend to have expenditure levels that are comparable with those of households with higher income levels (and slightly above the average expenditures recorded for the fifth decile), indicating that these households have access to economic resources, such as wealth, or that the instance of low or negative income is temporary, perhaps reflecting business or investment start-up. In this survey, persons reporting negative income have been grouped in the lowest weekly income ranges ($0-$499).
RELIABILITY OF ESTIMATES
15 The estimates provided in this survey are subject to sampling and non-sampling error.
16 Sampling error is the difference between the published estimates, derived from a sample of persons, and the value that would have been produced if all persons in scope of the survey had been included.
17 Non-sampling error may occur in any collection, whether it is based on a sample or a full count such as a census. Sources of non-sampling error included non-response, errors in reporting by respondents or recording of answers by interviewers, and errors in coding and processing data. Every effort is made to reduce the non-sampling error to a minimum by careful design of questionnaires, intensive training and supervision of interviewers and effective processing procedures.
IMPUTATION FOR NON-RESPONSE
18 Certain data items such as estimates of income had significant non-response for the 2007-08 MPHS. The ABS has not applied any imputation methodology for estimation of values for non-responses.
COMPARABILITY WITH MONTHLY LFS STATISTICS
19 Due to differences in the scope and sample size of the MPHS 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.
2007-2008 MPHS OUTPUTS
20 The MPHS is designed to collect statistics for a number of small, self-contained topics. These include both labour topics and other social and economic topics. The topics collected in 2007-08 were:
21 The MPHS also collects other socio-demographic information such as educational attainment, labour force status and personal and household income.
22 Data for other MPHS topics collected in 2007-08 is released in separate publications. In addition, data from the 2007-08 MPHS was released as an expanded Confidentialised Unit Record File (CURF) in early 2009.
CONFIDENTIALISED UNIT RECORD FILE
23 Confidentialised Unit Record Files (CURF) release confidentialised microdata from surveys, thereby facilitating interrogation and analysis of data. For all MPHS topics covered in the 2007-08 survey, an expanded CURF was published 27 January 2009. For more information on expanded CURFs refer to ABS information paper Multi-Purpose Household Survey, Expanded Confidentialised Unit Record File, Technical Manual (cat. no. 4100.0).
24 The ABS plans to conduct this survey again during the 2011-12 financial year.
25 ABS publications draw extensively on information provided freely by individuals, businesses, governments and other organisations. Their continued cooperation is very much appreciated. Without it, the wide range of statistics published by the ABS would not be available. Information received by the ABS is treated in strict confidence as required by the Census and Statistics Act 1905.
26 Other ABS publications that may be of interest are shown below, and are available at <www.abs.gov.au>:
Environmental Issues: People's Views and Practices, Mar 2007, (cat. no. 4602.0) -1994 to 2007 Issues
27 Non-ABS sources which may be of interest can be accessed through the Environment theme page on the ABS web site <www.abs.gov.au> found under the headings "Themes", "Environment and Energy", then "Environment".
28 Information about current publications and other products released by the ABS is available from the statistics page on the ABS website <www.abs.gov.au>. The ABS also issues a daily Release Advice on the website which details products to be released in the week ahead.
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