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5 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 detail.
6 The MPHS was conducted as a supplement to the monthly LFS. Each month, one eighth of the dwellings in the LFS sample were rotated out of the survey and a sub-sample of these dwellings was then selected for the MPHS. In these dwellings, after the LFS had been fully completed for each person in scope and coverage, a person aged 18 years or over was selected at random (based on a computer algorithm) and asked the various MPHS topic questions in a personal interview. Data was collected using Computer Assisted Interviewing, whereby responses were recorded directly onto an electronic questionnaire in a notebook computer, usually during a telephone interview.
7 For the 2011–12 MPHS, the sample was accumulated over a twelve month period from July 2011 to June 2012.
8 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, and consequently to the MPHS. It also contains definitions of demographic and labour force characteristics, and information about telephone interviewing.
9 The sample for the Attitudes to the Environment Survey was approximately 19,500. After taking into account sample loss, the response rate for the survey was 78%. In total, information was collected from 12,937 fully responding households.
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 enumerated person. The weight is a value which indicates the number of persons in the population represented by the sample person.
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. For example, if the probability of a person being selected in the survey was 1 in 600, then the person would have an initial weight of 600 (that is, they represent 600 people).
12 The initial weights are then calibrated to align with independent estimates of the population, referred to as benchmarks. The population included in the benchmarks is the survey scope. This calibration process ensures that the weighted data conform to the independently estimated distribution of the population described by the benchmarks 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.
13 The survey uses estimated resident population (ERP) based person benchmarks for each state and territory of Australia, as at 31 March 2012.
14 Survey estimates of counts of persons are obtained by summing the weights of persons with the characteristic of interest.
RELIABILITY OF ESTIMATES
15 Estimates in this publication are subject to sampling and non-sampling errors:
16 Information recorded in this survey is essentially 'as reported' by respondents and hence may differ from that which might be obtained from other sources or via other methodologies. This factor should be considered when interpreting the estimates in this publication.
17 Information was collected on respondents' perceptions on the condition of the natural environment. Perceptions are influenced by a number of factors and can change quickly. Care should therefore be taken when analysing or interpreting the data.
18 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 obtained from the LFS.
19 The ABS seeks to maximise consistency and comparability of estimates over time by minimising changes to its survey. However, sound survey practice requires ongoing review to maintain and improve the integrity of the data. Significant changes have been outlined below:
20 Country of birth data are classified according to the Standard Australian Classification of Countries (Second Edition) (SACC), 2008 (cat. no. 1269.0).
21 Area of usual residence is classified according to the Statistical Geography: Volume 1 – Australian Standard Geographical Classification (ASGC), 2006 (cat. no. 1216.0).
22 Educational attainment data are classified according to the Australian Standard Classification of Education (ASCED), 2001 (cat. no. 1272.0).
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