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Changes to the survey sample
7 The expansion in the 2009–10 sample for an extra 4,200 households was maintained in the 2013–14 SIH. This additional sample of households outside capital cities better supports Council of Australian Governments (COAG) performance indicator reporting, particularly in regard to housing affordability and home ownership measures required under COAG intergovernmental agreements.
8 In 2007–08, the ABS revised its standards for household income statistics following the adoption of new international standards in 2004 and review of aspects of the collection and dissemination of income data. The income estimates from 2007–08 onwards apply the new income standards, and are not directly comparable with estimates for previous cycles. The change in income level in 2007–08 is partly due to the change in methods but also partly due to real change in income. To the extent possible, the estimates for 2003–04 and 2005–06 shown in the time series tables also reflect the new treatments.
9 For more detail on the nature and impact of the changes on the income data see Appendix 4 of Household Income and Income Distribution, Australia, 2007-08 (cat. no. 6523.0).
CONCEPTS AND DEFINITIONS
10 The concepts and definitions relating to income statistics are described in the following section of this publication. Other definitions are included in the ‘Glossary’ section of this publication.
Person and household data
11 Income is a major determinant of economic wellbeing for most people and households. While income is usually received by individuals, it is normally shared between partners in a couple relationship and, often, with dependent children. To a lesser extent, it may be shared with other children, other relatives and possibly other people living in the same household, for example through the provision of free or reduced accommodation costs. Even when there is no transfer of income between members of a household, and no provision of free or reduced accommodation costs, household members are still likely to benefit from the economies of scale that arise from sharing dwellings.
12 Income and wealth have a collective effect at the household level. As a result, households are the main unit of analysis in this publication. However, it is the number of people who belong to households with particular characteristics, rather than the number of households with those characteristics, that is of primary interest in measuring income distribution and leads to the preference for the equal representation of those persons in such analysis. For example, if the person is used as the unit of analysis rather than the household, then the representation in the income distribution of each person in a household comprising four persons is the same as that for each person in a two person household. In contrast, if the household were to be used as the unit of analysis, each person in the four person household would only have half the representation of each person in the two person household.
13 In this publication, the income distribution measures are all calculated with respect to persons, including children. Such measures are sometimes known as person weighted estimates. They are described in more detail in the User Guide. Nevertheless, as most of the relevant characteristics of persons relate to their household circumstances, data cubes available from the ‘Downloads’ tab of this publication primarily describe the households to which people belong.
14 Household income consists of all current receipts, whether monetary or in kind, that are received by the household or by individual members of the household, and which are available for, or intended to support, current consumption.
15 Income includes receipts from:
16 Receipts of Family Tax Benefit are treated as income, regardless of whether they are received fortnightly or as a lump sum. The Baby Bonus was introduced in July 2004, and has now been replaced by a rate increase of Family Tax Benefit Part A from 1 March 2014. The Paid Parental Leave payment has also been included as income.
17 The aged persons' savings bonus and self-funded retirees' supplementary bonus, paid as part of the introduction of The New Tax System in 2000–01 are regarded as capital transfers as they were designed to help retired people maintain the value of their savings and investments following the introduction of the GST. However, the one-off payment to older Australians paid in 2000–01, 2005–06 and 2007–08, the one-off payment to families paid since 2003–04, and the one-off payments to carers paid since 2003–04, are included as income as they were primarily a supplement to existing income support payments.
18 The Clean Energy Supplement paid from March 2013 to January 2014 is included in income from government pensions or allowances. This tax-exempt, indexed payment was paid to pensioners, other income support recipients, families receiving Family Tax Benefit payments and Seniors Supplement recipients, provided they meet eligibility requirements.
19 The biannual Schoolkids bonus payment that was paid to eligible families, carers and students from January 2013 to December 2016 has been included in income from government pensions and allowances. This biannual payment, paid in January and July, was made payable to families receiving Family Tax Benefit Part A. Young people enrolled in school who were receiving Youth Allowance and other income support or veterans' payments are also entitled to this payment, providing that they meet the age and education requirements.
20 Gross income is the sum of income from all sources before income tax and the Medicare levy have been deducted. Prior to 2005–06, Family Tax Benefit paid through the tax system or as a lump sum was excluded from gross income for practical reasons but deducted in deriving disposable income. Since 2005–06 these payments have been included in gross income.
21 Disposable income better represents the economic resources available to meet the needs of households. It is derived by deducting estimates of personal income tax and the Medicare levy from gross income. Medicare levy surcharge was also calculated and deducted from gross income while calculating disposable income (as it was for the first time in 2007–08).
22 Income tax is estimated for all households using taxation criteria for 2013–14 and the income and other characteristics of household members reported in the survey.
23 Prior to 2005–06 the derivation of disposable income also included the addition of family tax benefit paid through the tax system or as a lump sum by Centrelink since for practical reasons it was not included in the gross income estimates.
Equivalised disposable income
24 Most analyses in this publication use equivalised disposable household income rather than gross or disposable income. Using an equivalising factor for household income enables the direct comparison of the relative economic wellbeing of households of different size and composition.
25 Equivalised disposable household income is calculated by adjusting disposable income by the application of an equivalence scale. The scale is based on the principle that larger households require a higher level of income to achieve the same standard of living as a smaller household. However, there are economies of scale, so each additional person does not equally add to the income needed to support household consumption.
26 Whereas disposable income includes negative values, these are adjusted to zero for the purpose of equivalised disposable household income.
27 After household income is adjusted according to an equivalence scale, the equivalised income can be viewed as an indicator of the economic resources available to a standardised household. For a lone person household, it is equal to income received. For a household comprising more than one person, equivalised income is an indicator of the household income that would be required by a lone person household in order to enjoy the same level of economic wellbeing as the household in question.
28 For more information on equivalised income, see the User Guide.
Lowest income decile
29 Throughout the next few paragraphs, the terms quintile, decile and percentile are used. If a distribution, such as household income, is put in order from lowest to highest, and then divided into 100 equal groups, each group is a percentile. Ten percentiles make up a decile (ten equal groups) and twenty percentiles make up a quintile.
30 Equivalised income generally provides a useful indicator of economic wellbeing. However, some households report extremely low and even negative income in the survey, which places them well below the safety net of income support provided by government pensions and allowances. Households may under report their incomes in the survey at all income levels, including low income households. Households may also correctly report low levels of income if they have incurred losses in their unincorporated business or have negative returns from other investments.
31 Studies of income and expenditure reported in HES surveys have shown that such households in the bottom income decile and with negative gross incomes tend to have expenditure levels that are comparable to those of households with higher income levels (and slightly above the average expenditures recorded for the fifth income decile). This suggests 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. Other households in the lowest income decile in past surveys had average incomes at about the level of the single pension rate, were predominantly single person households, and their main source of income was largely government pensions and allowances. However, on average, these households also had expenditures above the average of the households in the second income decile, which is not inconsistent with the use of assets to maintain a higher standard of living than implied by their incomes alone.
32 Other households in the lowest income decile in past surveys
However, on average, these households also had expenditures above the average of the households in the second income decile, which may be because these households are using assets to maintain a higher standard of living than their income alone could allow.
33 Some of the households included in the lowest income decile are unlikely to be suffering extremely low levels of economic wellbeing. Income distribution analysis may lead to inappropriate conclusions if such households are used as the basis for assessing low levels of economic wellbeing.
34 For this reason, in previous surveys, tables showing statistics classified by income quintiles included a supplementary category comprising the second and third income deciles, which were used as an alternative to the lowest income quintile.
35 More recent analysis suggests that this approach may have over-estimated the economic wellbeing of low income households, and unnecessarily excluded some of the most vulnerable households in the lowest income decile. The 2013–14 SIH uses an adjusted lowest income quintile instead, which is made up of the lowest two deciles, excluding the first and second percentiles. This adjusted lowest income quintile has been calculated for previous cycles to create a time series of these data, available from the ‘Downloads’ tab of this publication.
36 Income is collected using a number of different reporting periods. The reporting period is the whole financial year for own unincorporated business and investment income. In contrast, for wages and salaries, other sources of private income and government pensions and allowances, the reporting period is the most recent or usual payment, close to the time of interview. The income reported is divided by the number of weeks in the reporting period. Estimates of weekly income in this publication do not therefore refer to a given week within the reference period of the survey.
37 The tables in the main body of this publication refer to 'current' weekly income, that is, income being received at the time the data were collected from respondents. The survey also produces measures of 'annual' income that reflect total incomes for the previous financial year. The User Guide explains how current income differs from annual income, notes some of the advantages and disadvantages of the two types of measure and presents some 'annual' income estimates.
38 Imputed rent is an estimate of the amount of money that owner occupiers would have spent on housing if they were renting. The ABS estimates imputed rent to be able to compare household characteristics such as income across tenure types (owners, renters, non-market renters). Imputed rent may be understood as an adjustment to the income which takes into account the savings made by owning the household home. Gross imputed rent is an estimate of how much it would cost to rent the household home. Net imputed rent is gross imputed rent with housing costs (such as repairs and insurance) removed.
39 The ABS is implementing a new methodology for estimating gross imputed rent for household level estimates in the 2013–14 SIH. Although the methodology for deriving net imputed rent is unchanged, the net imputed rent estimates are impacted by the change in gross imputed rent estimates.
40 Imputed rent estimates for the 2013–14 SIH will be available in a secondary release of SIH data. An information paper detailing the new methodology will be released on the ABS web site at the same time, titled: Information paper: New methodology for estimating gross imputed rent in the Survey of Income and Housing (cat. no. 6525.0.55.001).
41 The new methodology replaces the previous Hedonic regression methodology that was used to derive imputed rent estimates in each SIH from 2003–04 to 2011–12. For more information on the previous methodology and the derivation of net imputed rent, see Experimental Estimates of Imputed Rent, Australia, 2003–04 and 2005–06 (cat. no. 6525.0).
42 The availability of imputed rent estimates allows the analysis of household income to be extended to include the imputed rental incomes that flow to people living in homes owned by the occupant and those paying subsidised rent. Such imputations allow for more meaningful comparison of the income circumstances of people living in different tenure types, and to understand changes over time in income levels and the distribution of income when tenures may be changing over time. Including imputed rent as part of household income and expenditure conceptually treats owner occupiers as if they were renting their home from themselves, thus simultaneously incurring rental expenditure and earning rental income. Imputed rent is included in income on a net basis i.e. the imputed value of the services received less the value of the housing costs incurred by the household in their role as a landlord.
43 Net imputed rent is estimated as gross imputed rent less reported housing costs. For owner occupiers, the housing costs subtracted are those which would normally be paid by landlords i.e. rates, mortgage interest, insurance, repairs and maintenance. For households paying subsidised rent (e.g. tenants of an employer or of a state/territory housing authority) and households occupying their dwelling rent-free, the housing costs that are subtracted are largely made up of the reported rent paid, but other housing costs incurred, such as rates, are also subtracted for some tenure types.
Child care payments
44 Childcare subsidies assist families with dependent children with the costs of childcare. Two subsidies are collected and modelled in the 2013–14 SIH. These are Childcare Benefit and Childcare Rebate.
45 Child Care Benefit (CCB) is a payment from the Australian Government that assists families with the costs of registered or approved child care. The scheme is means-tested and allocates an hourly amount that can either be provided to child care consumers after child care has been paid, or directly to child care providers, thereby reducing the upfront child care fees payable by the consumer.
46 Child Care Rebate (CCR) is also an Australian Government payment that, like CCB, assists families with the cost of child care. Each childcare consumer is entitled to CCR, which is 50% of their net childcare costs. That is, a childcare consumer is entitled to 50% of their childcare costs after CCB has been deducted from the cost if they receive it, or else 50% of the whole cost. CCR payments accrue up to a per child, per year limit ($7,500 per child per year in 2013–14). Families are eligible for CCB for up to 50 hours a week per child. CCR, like CCB, may be paid either to the consumer in a lump sum or directly to childcare providers, thereby further reducing the upfront cost of childcare.
47 Estimates of CCB and CCR are collected from the child care questions, however there has been a substantial gap between the reported number of households receiving childcare subsidies and the total value of that assistance, compared to administrative records. In 2013–14 SIH, CCB and CCR have been modelled to improve the estimates of these payments. The output data is made up of both reported and modelled data. Child care assistance is conceptually treated as social transfers in kind, including administrative overhead as part of the value of the transfer.
Social transfers in kind
48 Social transfers in kind consist of goods and services provided free or at subsidised prices by the government. The allocation of social transfers in kind presented in this publication is restricted to government expenditure that is relatable to particular types of households. Information reported in the 2013–14 SIH was used as the basis for allocating social transfers in kind for the provision of education, health, housing, child care, electricity concessions and other social security and welfare services.
49 The total value of social transfers in kind was defined as Commonwealth, state or territory and local government expenses, net of intra-government transfers, minus government pensions and allowances paid in cash minus government revenue from the sale of goods and services.
50 The User Guide provides estimates of social transfers in kind and outlines the methodologies used to allocate the social transfers in kind to individual households in 2013–14.
51 Net worth, often referred to as wealth, is the value of a household's assets less the value of its liabilities. Assets can take many forms including:
52 Liabilities are primarily the value of loans outstanding including:
53 In the 2013–14 SIH, some asset and liability data were collected on a net basis rather than collecting for each component listed above. In particular, if a survey respondent owned or part owned a business, they were asked how much they would receive if they sold their share of the business and paid off any outstanding debts.
54 The survey collects information by personal interview from usual residents of private dwellings in urban and rural areas of Australia (excluding very remote areas), covering about 97% of the people living in Australia. Private dwellings are houses, flats, home units, caravans, garages, tents and other structures that were used as places of residence at the time of interview. Long-stay caravan parks are also included. These are distinct from non-private dwellings which include hotels, boarding schools, boarding houses and institutions. Residents of non-private dwellings are excluded.
55 Usual residents excludes:
56 Information for each household was collected using:
57 Sample copies of the above documents are included in the Survey of Income and Housing, User Guide, Australia, 2013–14 (cat. no. 6553.0).
58 The sample was designed to produce reliable estimates for broad aggregates for households resident in private dwellings aggregated for Australia, for each state and for the capital cities in each state and territory. More detailed estimates should be used with caution, especially for Tasmania, the Northern Territory and the Australian Capital Territory.
59 For the 2013-14 SIH, dwellings were selected through a stratified, multistage cluster design from the private dwelling framework of the ABS Population Survey Master Sample. Selections were distributed across a twelve month enumeration period so that the survey results are representative of income patterns across the year.
60 Of the selected dwellings there were 18,249 households in the scope of the survey. Of these, 20% did not respond at all to the questionnaire, or did not respond adequately. Most of these were not able to be contacted during the survey enumeration or were contacted but either refused to respond or was not able to respond. The remainder of these households included:
Partial response and imputation
61 Some households did not supply all the required information but supplied sufficient information to be retained in the sample. Such partial response occurs when:
62 If there is sufficient response to retain the household, then the missing data are imputed by replacing each missing value with a value reported by another person (referred to as the donor).
63 Donor records are selected by finding fully responding persons with matching information on various characteristics (such as state, sex, age, labour force status and income) as the person with missing information. As far as possible, the imputed information is an appropriate proxy for the information that is missing. Depending on which values are to be imputed, donors are randomly chosen from the pool of individual records with complete information for the block of questions where the missing information occurs.
64 The final SIH sample includes 5,613 households which had at least one imputed value in income, assets and liabilities, or child care expenses. For 40% of these households only a single module was missing data.
65 The final sample on which estimates were based is composed of persons for which all necessary information is available. The information may have been wholly provided at the interview (fully-responding) or may have been completed through imputation for partially responding households. Of the selected dwellings there were 18,249 in the scope of the survey, of which 14,162 (78%) were included as part of the final estimates.
67 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 (e.g. a person or a household). 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 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 household being selected in the survey was 1 in 600, then the household would have an initial weight of 600 (that is, it represents 600 households).
68 An adjustment is then made to the initial weights to ensure that seasonal variation is appropriately represented in survey estimates. After this initial adjustment, the sum of the weights of households in each quarter is in proportion to the length of the quarter (which align across the financial year with pension indexation dates rather than calendar quarters).
69 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.
70 Most of the independent person and household benchmarks are based on demography estimates of numbers of persons and households in Australia. The benchmarks are adjusted to include persons and households residing in private dwellings only and to exclude persons living in very remote areas, and therefore do not, and are not intended to, match estimates of the Australian resident population published in other ABS publications. The demography estimates of persons (estimated resident population - ERP) and households used in SIH 2013–14 are built up from the 2011 Census.
71 In the 2013–14 SIH, as in 2007–08, 2009–10 and 2011–12, all persons in each household were assigned a weight. This differs from the 2005–06 SIH where children aged 0–14 years were not given separate weights, but household counts of the number of children were benchmarked to population totals.
72 The benchmarks used in the calibration of the final weights for the 2013–14 SIH were:
73 Estimates produced from the survey are usually in the form of averages (e.g. average weekly income of couple households with dependent children), or counts (e.g. total number of households that own their dwelling or total number of persons living in households that own their own dwelling). For counts of households, the estimate was obtained by summing the weights for the responding households in the required group (e.g. those owning their own dwelling). For counts of persons, the household weights were multiplied by the number of persons in the household before summing. The SIH collects data on the number of people, including children, in each household but separate records with income and most detailed data were only collected for people 15 years and older.
74 Average income values are obtained in two different ways, depending on whether mean gross household income or mean equivalised disposable household income is being derived. Estimates of mean gross household income are calculated on a household weighted basis. They are obtained by multiplying the gross income of each household by the weight of the household, summing across all households and then dividing by the estimated number of households. For example, the mean gross household income of couple households with dependent children is the weighted sum of the gross income of each such household divided by the estimated number of those households.
75 Estimates of mean equivalised disposable household income are calculated on a person weighted basis. They are obtained by multiplying the equivalised disposable income of each household by the number of people in the household (including children) and by the weight of the household, summing across all households and then dividing by the estimated number of people in the population group. The User Guide illustrates the differences between mean gross household income calculated on a household weighted basis and mean equivalised disposable household income calculated on a person weighted basis.
RELIABILITY OF ESTIMATES
76 The estimates provided in this publication are subject to two types of error, non-sampling and sampling error.
77 Non-sampling error can occur in any collection, whether the estimates are derived from a sample or from a complete collection such as a census. Sources of non-sampling error include non-response, errors in reporting by respondents or recording of answers by interviewers and errors in coding and processing the data.
78 Non-sampling errors are difficult to quantify in any collection. However, every effort is made to reduce non-sampling error to a minimum by careful design and testing of the questionnaire, training of interviewers and data entry staff and editing and quality control procedures during data processing.
79 One of the main sources of non-sampling error is non-response by persons selected in the survey. Non-response occurs when people cannot or will not cooperate or cannot be contacted. Non-response can affect the reliability of results and can introduce a 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.
80 The following methods were adopted to reduce the level and impact of non-response:
81 The estimates are based on a sample of possible observations and are subject to sampling variability. The estimates may therefore differ from the figures that would have been produced if information had been collected for all households. A measure of the sampling error for a given estimate is provided by the standard error, which may be expressed as a percentage of the estimate (relative standard error). Further information on sampling error is given in the User Guide.
82 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.
SPECIAL DATA SERVICES
83 The ABS offers specialist consultancy services to assist clients with more complex statistical information needs. Clients may wish to have the unit record data analysed according to their own needs, or require tailored tables incorporating data items and populations as requested by them. Tables and other analytical outputs can be made available electronically or in printed form. However, as the level of detail or disaggregation increases with detailed requests, the number of contributors to data cells decreases. This may result in some requested information not being able to be released due to confidentiality or sampling variability constraints. All specialist consultancy services attract a service charge, and clients will be provided with a quote before information is supplied.
UNIT RECORD FILE
85 A Basic confidentialised unit record file (CURF) from the 2013–14 SIH will be released in November 2015 on CD-ROM and via the Remote Access Data Laboratory (RADL). A more detailed (Expanded) SIH CURF will also be available through the RADL and ABS Data Laboratory (ABSDL). To access the SIH 2013–14 Basic and Expanded CURFs refer to the How to Apply for Microdata web page. Clients should familiarise themselves with the User Manual: Responsible Use of ABS CURFs and other related microdata information which are available via the Microdata web pages, before applying for access through MiCRO.
86 The ABS/Universities Australia Agreement provides participating universities with access to a range of ABS products and services. This includes access to CURF data. For further information, university clients should refer to the ABS/Universities Australia Agreement web page.
88 The Survey of Income and Housing, User Guide, Australia, 2013–14 (cat. no. 6553.0) includes information about the purpose of the survey, the concepts and contents, and the methods and procedures used to collect the data and derive the estimates. It also outlines the differences between the 2013–14 survey and earlier SIH surveys. Its purpose is to help users of the data understand the nature of the survey, and its potential to meet user needs. It also contains information for users of the SIH confidentialised unit record files (CURFs).
89 Refer to the ‘Related Information’ tab of this publication for other ABS publications which may be of interest.
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