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EXPLANATORY NOTES
4 A full list of the data items from the 2010 GSS is contained in the General Social Survey: User Guide (cat. no. 4159.0.55.002) to be released in October 2011. SCOPE OF THE SURVEY 5 Only people who were usual residents of private dwellings in Australia were covered by the General Social Survey (GSS). Private dwellings are houses, flats, home units and any other structures used as private places of residence at the time of the survey. People who usually reside in non-private dwellings such as hotels, motels, hostels, hospitals and short-stay caravan parks were not included in the survey. Usual residents are those who usually live in a particular dwelling and regard it as their own or main home. Visitors to private dwellings are not included in the interview for that dwelling. However, if they are a usual resident of another dwelling that is in the scope of the survey they have a chance of being selected in the survey or, if not selected, they will be represented by similar persons who are selected in the survey. 6 The GSS was conducted in both urban and rural areas in all states and territories, except for very remote parts of Australia. This exclusion is unlikely to impact on national estimates, and will only have a minor impact on any aggregate estimates that are produced for individual states and territories, except the Northern Territory where the excluded population accounts for over 20% of persons. 7 The Australian population at September 2010, after exclusion of people living in non-private dwellings and very remote areas of Australia, was 21,836,200, of which 16,788,159 were aged 18 years and over. 8 The following non-residents were excluded from resident population estimates used to benchmark the survey results, and were not interviewed:
SAMPLE DESIGN 9 The GSS was designed to provide reliable estimates at the national level and for each State and Territory. The sample was therefore spread across the states and territories in order to produce estimates that have a relative standard error (RSE) of no greater than 10% for characteristics that are relatively common in the national population, say that at least 10% of the population would possess. 10 For the 2010 cycle, the standard sampling methodology was adapted in order to provide better estimates of people experiencing disadvantage. Using Census 2006 data and a proxy indicator of disadvantage, areas with high concentrations of people experiencing disadvantage were given a higher probability of selection in the survey. Households were then randomly selected from each area selected to participate in the survey. 11 The initial sample for the survey consisted of approximately 19,576 private dwellings. This number was reduced to approximately 17,158 dwellings due to the loss of households which had no residents in scope for the survey and where dwellings proved to be vacant, under construction or derelict. Of the eligible dwellings, 87.6% responded fully (or adequately) which yielded a total sample from the survey of 15,028 dwellings. 12 Some survey respondents provided most of the required information, but were unable or unwilling to provide a response to certain data items. The records for these persons were retained in the sample and the missing values were recorded as 'don't know or not stated'. No attempt was made to deduce or impute for these missing values. Approximately 2,551 respondents (15%) did not provide one or more required answers but were deemed to have responded adequately. Details of missing values for data items are presented in paragraph 34. DATA COLLECTION 13 ABS Interviewers conducted personal interviews using a Computer Assisted Interviewing (CAI) questionnaire at selected dwellings during the period August to November 2010. CAI involves the use of a notebook computer to record, store, manipulate and transmit the data collected during interviews. 14 Much of the detail obtained from the GSS was provided by one person aged 18 years or over, randomly selected from each participating household. The random selection of this person was made once basic information had been obtained about all household members. Some financial and housing items collected in the GSS required the selected person to answer on behalf of other members of the household. In some cases, particularly where household information was not known by the selected person, a spokesperson for the household was nominated to provide household information. 15 A copy of the 2010 GSS interview questions is available in the General Social Survey: User Guide (cat. no. 4159.0.55.002). WEIGHTING, BENCHMARKING AND ESTIMATION Weighting 16 Weighting is the process of adjusting results from a sample survey to infer results for the total in-scope population whether that be persons or households. To do this, a 'weight' is allocated to each sample unit i.e. a person or a household. The weight is a value which indicates how many population units are represented by the sample unit. 17 The first step in calculating weights for each person or household 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 600, then the person would have an initial weight of 600 (that is, they represent 600 people). Benchmarking 18 The initial weights are then calibrated to align with independent estimates of the population of interest, referred to as 'benchmarks'. 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. 19 The GSS was benchmarked to the in scope estimated resident population (ERP) and the estimated number of households in the population. The 2010 GSS used population and household benchmarks based on the 2006 Census. 20 Given that the GSS heavily sampled areas of multiple social disadvantage, further analysis was undertaken to ascertain whether benchmark variables, in addition to geography, age, and sex, should be incorporated into the weighting strategy. Analysis showed that the standard weighting approach did not adequately compensate for differential undercoverage in the 2010 GSS sample for variables such as SEIFA and labour force status, when compared to other ABS surveys. As these variables were considered to have possible association with social characteristics, additional benchmarks were incorporated into the weighting process. 21 The benchmarks used in the calibration of final weights for the 2010 GSS were:
ESTIMATION 22 Survey estimates of counts of persons are obtained by summing the weights of persons or households with the characteristic of interest. Estimates for means, such as mean age of persons, are obtained by summing the weights of persons in each category (e.g. individual ages), multiplying by the value for each category, aggregating the results across categories, then dividing by the sum of the weights for all persons. 23 The majority of estimates shown in this publication are based on benchmarked person weights. The estimates of mean incomes, mortgages and rents contained in tables 5 and 17-23 are based on benchmarked household weights. Means for the number of persons and the number of employed persons in table 5 are also based on benchmarked household weights. RELIABILITY OF ESTIMATES 24 All sample surveys are subject to error which can be broadly categorised as either sampling error or non-sampling error. Sampling error occurs because only a small proportion of the total population is used to produce estimates that represent the whole population. Sampling error can be reliably measured as it is calculated based on the scientific methods used to design surveys. Non-sampling errors occur when survey processes work less effectively than intended. For example, some persons selected for the survey may not respond (non-response); some survey questions may not be clearly understood by the respondent; and occasionally errors can be made in processing data from the survey. Sampling error 25 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. For more information refer to the 'Technical notes'. Sampling error is measured for this survey by relative standard errors (RSEs). In this publication estimates with RSEs of 25% to 50% are preceded by an asterisk (e.g. *3.4) to indicate that the estimate should be used with caution. Estimates with RSEs over 50% are indicated by a double asterisk (e.g.**0.6) and should be considered unreliable for most purposes. Non-sampling error 26 One of the main sources of non-sampling error is non-response by persons selected in the survey. Non-response can affect the reliability of results and can introduce bias. The magnitude of any bias depends upon the level of non-response and the extent of the difference between the characteristics of those people who responded to the survey and those who did not. 27 To reduce the level and impact of non-response, the following methods were adopted in this survey:
28 Of the dwellings selected in the 2010 GSS, 12% did not respond fully or adequately. As the non-response to the GSS was low, the impact of non-response bias is considered to be negligible. 29 Every effort was made to minimise other non-sampling error by careful design and testing of questionnaires, intensive training and supervision of interviewers, and extensive editing and quality control procedures at all stages of data processing. 30 An advantage of the CAI technology used in conducting interviews for this survey is that it potentially reduces non-sampling errors by enabling edits to be applied as the data are being collected. The interviewer is alerted immediately if information entered into the computer is either outside the permitted range for that question, or contradictory to information previously recorded during the interview. These edits allow the interviewer to query respondents and resolve issues during the interview. CAI sequencing of questions is also automated such that respondents are asked only relevant questions and only in the appropriate sequence, eliminating interviewer sequencing errors. SEASONAL EFFECTS 31 The estimates in this publication are based on information collected from August to November 2010, and due to seasonal effects they may not be fully representative of other time periods in the year. For example, the GSS asked standard ABS questions on labour force status to determine whether a person was employed. Employment is subject to seasonal variation through the year. Therefore, the GSS results for employment could have differed if the GSS had been conducted over the whole year or in a different part of the year. INTERPRETATION OF RESULTS 32 Care has been taken to ensure that the results of this survey are as accurate as possible. All interviews were conducted by trained ABS Interviewers. Extensive reference material was developed for use in the field enumeration and intensive training was provided to interviewers in both classroom and on-the-job environments. There remain, however, other factors which may have affected the reliability of results, and for which no specific adjustments can be made. The following factors should be considered when interpreting these estimates:
33 Further information on the interpretation of results is contained in the General Social Survey: User Guide (cat. no. 4159.0.55.002). 34 For a number of GSS data items, some respondents were unwilling or unable to provide the required information. No imputation was undertaken for this missing information. Where responses for a particular data item were missing for a person or household they were recorded in a 'not known or not stated' category for that data item. These 'not known or not stated' categories are not shown in the publication tables. However, the person or household has been included in the total for most data items. The exception is the equivalised gross household income data item where it was more appropriate to calculate percentages excluding the missing values. Below is a table showing the number and proportion of missing values for key GSS data items. KEY GSS DATA ITEMS WITH A 'NOT KNOWN OR NOT STATED' CATEGORY
35 For persons or households reporting nil or negative total income, or where the income amount was unknown, the principal source of income has been classified as 'undefined'. An estimated 330,000 people (2%) live in households where the principal source of income was 'undefined'. CLASSIFICATIONS 36 Occupation data were classified according to the Australian and New Zealand Standard Classification of Occupations, First Edition, 2006 (cat. no. 1220.0). 37 Country of birth data were classified according to the Standard Australian Classification of Countries (SACC), Second Edition, 2008 (cat. no. 1269.0). 38 Area data (Capital city, Balance of state/territory; Remoteness areas) are classified according to the Australian Standard Geographical Classification (ASGC), 2006 (cat. no. 1216.0). COMPARABILITY WITH 2006 GSS 39 Selected summary results from the 2002 and 2006 GSS are presented in this publication to provide comparisons over time. The statistical significance of differences in estimates between 2006 and 2010 have been investigated and results that are statistically significant are indicated in Table 1. While the scope, content and data collection were largely the same in both collections, the sample design and weighting procedures were not. Some differences are noted below. 40 The GSS is designed to collect information for a core set of topics in each cycle, to allow analysis of changes over time, and a cyclical component to collect additional information. Approximately 80% of the content of the 2006 GSS was repeated in the 2010 GSS. The differences in content between the surveys were in the cyclical component of the GSS. The cyclical component of the 2006 GSS included topics on household use of information technology, attendance at selected culture/leisure venues, participation in sport and recreational physical activities and volunteering. Summary indicators for these topics were also collected in the 2010 GSS to allow comparisons over time. 41 The cyclical component of the 2010 GSS included more detailed indicators of family and community involvement (i.e. indicators of social network structure, types, qualities and transactions) which along with closely related items from the 2006 GSS is sometimes referred to as being the 'social capital' component of the survey. The cyclical component also included items related to topics of experience of homelessness, social disorder, visa category, access to service providers and reasons did not undertake study or training. Some of this data may be included in the next cycle of the GSS, however in less detail. 42 The sample sizes differed between the 2010 and 2006 GSS. In 2010, the number of fully or adequately responding households achieved in the survey was 15,028 compared to approximately 13,375 for the 2006 cycle. The 2010 cycle had a larger initial sample size (19,576 possible dwellings) compared to the 2006 initial sample size (17,700 possible dwellings). In addition, the 2006 GSS experienced higher rates of sample loss because there were more households with no residents in scope for the survey or where dwellings proved to be vacant, under construction or derelict, and a higher rate of survey non-response from eligible households. These differences in the sample size for 2010 and 2006 should be considered when comparing results. 43 For the 2010 cycle, a change in sample design was adopted to obtain more observations of people exhibiting multiple disadvantage, to provide a richer dataset of the characteristics of this subpopulation. The sample design involved using Census 2006 data to target areas with higher concentrations of households experiencing multiple disadvantage. To compensate for over sampling, the weighting process included additional benchmarks. These differences in the sample design for 2010 and 2006 should be considered when comparing results. 44 The voluntary work estimates for 2010, and presented in tables 2 to 16 and table 30, exclude those persons who were compelled to do voluntary work because of employment or study commitments, for example, work for the dole. However, for time series comparison purposes, the voluntary work estimates presented in table 1 for 2002 and 2006 do not exclude these populations and therefore a higher rate of 'voluntary involvement' results. For further information on voluntary work, and for comparisons over time, refer to the publication Voluntary Work, Australia (cat. no. 4441.0). 45 The 2010 GSS collected visa status information from migrants who arrived in Australia after 1989 (i.e. 1990 or later) who obtained permanent Australian resident status, as well as people who were temporary residents of Australia for 12 months or more, excluding those born in New Zealand, those holding New Zealand citizenship and those who held Australian citizenship prior to their arrival in Australia. Several changes to question wording were made to the Visa Status module for the 2010 survey. These changes were made to increase respondent understanding of the questions. For this reason the visa category estimates for 2010, presented in tables 2 to 4 and table 44, are not comparable to the 2006 data. 46 A full list of the data items from the 2010 GSS is contained in the General Social Survey: User Guide (cat. no. 4159.0.55.002). The data item list contains information on the changes in content between the 2006 and 2010 collections. For published results from the 2006 GSS, refer to General Social Survey: Summary Results, Australia, 2006 (cat. no. 4159.0). Appendix 1: Comparison of Data from GSS and Other ABS Sources 47 This presents comparisons between a number of key GSS data items and similar data items from other ABS sources. Where possible, results from other surveys have been adjusted to the scope and coverage of the GSS (or vice versa). GSS PRODUCTS AND SERVICES 48 Below is information describing the range of data to be made available from the 2010 General Social Survey, both in published form and on request. Products available on the ABS web site are indicated accordingly. General Social Survey: Summary Results, Australia, 2010 Datacubes 49 The tables released in this product are in spreadsheet format and are available on the ABS web site (cat. no. 4159.0). Estimates, proportions and the related RSEs are presented for each table. General Social Survey: User Guide 2010 50 The GSS User Guide will be released in conjunction with the Confidentialised Unit Record File (CURF). It provides detailed information about the survey content, methodology and data interpretation. It also contains the list of GSS data items, survey questions and prompt cards. It is expected that the User Guide will be available free-of-charge on the ABS web site in October 2011 (cat. no. 4159.0.55.002). State/territory tabulations 51 Versions of the GSS national results tables are also compiled separately for each state and territory and are available on the ABS web site in. These tables will be customised depending on the size of the sampling error. They are in spreadsheet format under General Social Survey: States and Territories, 2010 (cat. no. 4159.0.55.003). Microdata 52 For users who wish to undertake more detailed analysis of the survey data, microdata from the 2010 GSS will be released in the form of two confidentialised unit record files (CURFs): Microdata: General Social Survey, CURF, Australia, 2010 (cat. no. 4159.0.30.003). The expanded CURF will contain more detail than the basic CURF and will only be available via the Remote Access Data Laboratory (RADL), which is a secure Internet-based data query service. The basic CURF will be available via CD ROM or RADL. Technical information describing the content and use of the basic and expanded GSS CURFs will be available within the GSS User Guide. The GSS basic and expanded CURFs and Technical Manual are expected to be available in October 2011. 53 Up-to-date information on the ABS RADL service, including information on pricing, 'Applications & Undertakings', and a training manual outlining obligations and responsibilities when accessing ABS microdata, is available on the ABS web site. Those wishing to access the 2010 GSS microdata should refer to the ABS Website <https://www.abs.gov.au> (see Services, ABS Microdata) and read the Microdata Entry Page, and other linked information, before downloading the appropriate Guide, Application and Undertaking forms and applying for access. University clients should refer to the ABS web site <www.abs.gov.au> (see Services, Services for Universities). The GSS basic and expanded CURFs can be accessed by universities participating in the ABS/Universities Australia Agreement for research and teaching purposes. Data available on request 54 Special tabulations of GSS data are available on request and for a fee. Subject to confidentiality and sampling variability constraints, tabulations can be produced from the survey incorporating data items, populations and geographic areas selected to meet individual requirements. These can be provided in printed or electronic form. Please refer to the contact details noted at the front of this publication. RELATED PUBLICATIONS 55 Current publications and other products released by the ABS are available on the ABS web site. ABS publications which may be of interest are:
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