Historical Information

A number of changes have been made to the Survey of Income and Housing (SIH) since it was first conducted. The changes were designed to improve the quality of the surveys, however, these may have an impact on the assessment of trends and indicators over time. This section outlines the main changes over time.

The final sample sizes for SIH cycles (from 1994–95) are shown in Table 1. The sample sizes can give an indication of the reliability of the estimates produced from the surveys.

To access information on the previous SIH cycles listed, see the 'Previous releases' section or the 'Historical information' section of this publication.

• collection methodology for 2019–20 included the introduction of a computer assisted web interview (or online form) where the respondent could self report (without interviewer assistance). As a result, estimates may not be directly comparable to previous cycles. For more information, please see the Household Income and Wealth, Australia - Methodology, 2019-20
• a general review of the questions, populations and sequencing was undertaken to optimise survey content for online collection
• the Household Form was redesigned as part of the Integrated Household Surveys Program to produce common content across various household surveys
• cyclical housing content was collected this cycle, including changes in rent payments which was last collected in 2007–08
• the Child care module was largely restructured for online collection and to address payment changes. The Child Care Rebate (CCR) and Child Care Benefit (CCB) were no longer collected for children aged 12 and under. The Child Care Subsidy (CCS) replaces the CCR and CCB and is now collected for children aged 13 and under
• superannuation: use of lump sum payments is not collected
• financial stress indicators have been altered comparative to what was collected in HIES ($500 emergency funds, heat cool home, dental treatment). Additional content on financial behaviours and resilience have been included, in line with the General Social Survey
• Social transfers in kind (STIK) data is no longer collected in cyclical housing years 
• changes in Government payments and allowances categories to reflect Department of Social Security reporting (such as Newstart allowance changed to JobSeeker allowance)
• family changes and smoking status modules were not collected for this cycle.

The 2017–18 SIH content was largely similar to the 2015–16 SIH with some changes in questions, definitions and methodology. Key changes to the SIH in the 2017–18 cycle include:

• additional questions to have been asked to collect further information about the living arrangements of usual residents aged under 20 years of age who live in the household some of the time, but also spend time living with a parent/guardian elsewhere. Further to that questions have also been asked to determine the living arrangement of children (aged under 20 years) who spend time at the household but are not considered a usual resident.
• superannuation balances are no longer disseminated based on whether it is a government or non-government fund
• child care imputation was improved in the 2017–18 cycle
• credit card and HECS debt information is now collected at the person level and aggregated to the household level
• changes in Government payments and allowances categories to reflect Department of Social Security reporting (such as the removal of Baby Bonus, School Kids Allowance and Utilities Allowance)
• removal of question regarding supplement amount as it is now estimated by the eligibility-based model designed by the Department of Social Security (model introduced in 2015–16)
• previous financial year income is no longer collected, except for business income
• business income question wording was improved to ensure franking credits were excluded from responses
• module on smoking status was included (output as part of National Health Survey) will be available on the SIH CURF, Tablebuilder and detailed file in the DataLab
• Australian Statistical Geography Standard (ASGS) 2011 has been used for sample selection and weighting. Both ASGS 2011 and 2016 will be available on the outputs
• the expansion in the 2009–10 sample for an extra 4,200 households outside capital cities to provide more detailed analysis of housing affordability and home ownership measures was maintained in the 2017–18 SIH cycle

Balance of other Superannuation account

In SIH 2017-18, an issue with the survey instrument occurred where the value of regular income received for other superannuation, annuities or private pension accounts was not asked. As a result, data for this item was modelled with a regression method using previous year's data where values were collected. For further information please refer to the 'Data Collection and Processing' chapter of this publication.

The 2015–16 SIH content was largely similar to the 2013–14 SIH with some changes in questions, definitions and methodology. Key changes to the SIH in the 2015–16 cycle include:

• the item identifying carers which was added in 2013–14 was not collected in 2015–16
• the processing of government payments information from the SIH and HES has been improved by the introduction of an eligibility-based model. Missing or anomalous government payments values are now produced by the model
  • the cyclical additional housing content first collected in 2007–08 and again in 2013–14 has been removed for 2015–16
  • there were changes to the methodology for imputed rent which are outlined further in the 'Imputed rent' chapter of this publication
• an index of service accessibility has been added to the survey data. The Metropolitan Accessibility/Remoteness Index of Australia (Metro ARIA) enables analysis of expenditure in relation to accessibility of services for metropolitan areas
• questions collected on solar energy usage that were collected in the Household Energy Consumption Survey in 2012 were collected in the 2015–16 SIH.

For the 2015–16 SIH and HES there was an additional sample of capital city households, targeting households whose main source of income was government pensions, benefits and/or allowances, this was last included in 2009–10 however changes were made to the screening and selection methodology for 2015–16. In this additional sample for 2015–16, dwellings were targeted using information from the previous HES (2009–10), and information from the Socio-Economic Indexes for Areas (SEIFA). Households were screened using a short questionnaire to identify whether pensions and benefits were likely to be the main source of income for the household. One in four households were selected to complete the combined SIH and HES questionnaire and diaries regardless of the screening outcome. Information from this sample were used to assess the outcomes from the screening questionnaire for the whole sub-sample. In 2015–16 the SIH and HES samples are not evenly balanced over the course of the year. Due to under-performance of the sample design in the first half of the collection year, a top-up sample was selected and collected from January – July 2016. Weights adjust by quarter to ensure representativeness across the year. For more information see the 'Sampling' chapter of this user guide.

Hours usually worked in second job

In SIH and HES 2015–16, an isolated issue with the survey instrument occurred where respondents working more than one job were not asked to specify the hours they usually worked in their second jobs. As a result, data for hours usually worked in the second job had to be modelled. For further information please refer to the 'Data Collection and Processing' chapter of this publication.

Government pensions and allowances

The Newborn Supplement and Newborn Upfront Payment replaced the Baby Bonus on 1 March 2014 and those eligible receive it as part of their Family Tax Benefit (FTB) Part A payments for a period of 13 weeks or with their lump sum and are therefore not output separately.

The Seniors Supplement for Commonwealth Seniors Health Card (CSHC) holders was ceased and no longer paid beyond June 2015.

The microediting of income from government payments has been improved in terms of accuracy. The ABS has introduced an eligibility-based model designed by the Department of Social Services. This model produces a value for every person aged 15 years or over for all government payments and allowances that are collected in the survey. The modelled amount is then compared to the reported government payment values to identify and edit values that are significantly higher than the maximum amount eligible, to impute missing values and to impute values for payments which are consequential on the basis of reported payments (e.g. a value for Utilities Allowance is allocated to all recipients of Partner Allowance, even those who did not separately report it). All other government payments' values remain as reported. Some payment values are entirely modelled based on eligibility as in previous cycles of SIH. Microdata products (e.g. the Basic CURF) will include both the reported and modelled values for comparison (except where the reported payment values were out of the possible range or missing).

The 2013–14 SIH content was largely similar to the 2011–12 SIH with some changes in questions, definitions and methodology. Key changes to the SIH in the 2013–14 cycle include:

• Australian Statistical Geography Standard (ASGS) 2011 has been used throughout the survey for sample selection, weighting and output. At the sub-state level, this required a break in the time series, with 2013–14 survey including Greater Capital City Statistical Area. Previous surveys used the Australian Standard Geographical Classification (ASGC)
• the expansion in the 2009–10 sample for an extra 4,200 households outside capital cities to support housing indicator reporting was maintained in the 2011–12 and 2013–14 cycles
• this cycle of SIH includes extra housing information last collected in 2007–08
• an item identifying carers has been added
• a new model of imputed rent has been designed and implemented, which will be available in an additional release
• data on the new Dad and Partner Pay Subsidy has been collected
• selected social transfers in kind variables have been modelled in 2013–14
• a decrease in fully responding sample size from 14,569 households in 2011–12 to 14,162 households in 2013–14 due to increased sample loss and slightly lower response rates
• additional information about lump sums drawn from superannuation
• franking credits were previously partly modelled and added to disposable income. For 2013-14, franking credits were modelled for all income from dividends and added to gross income
• inclusion of questions on disability status, concession cards held, educational institution attended and private health expenditure that were last collected in the 2009–10 HES.

The 2013–14 SIH sample design is similar to previous cycles of SIH with three main changes:

• Australian Statistical Geography Standard (ASGS) 2011 has been used for sample selection
• the introduction of a new master sample for all ABS Special Social Surveys
• change to the cluster fractions in each state by Part of State.

From 2013–14, the publication Household Income and Wealth, Australia, 2013–14 incorporates information previously presented as part of the Household Income and Income Distribution, Australia, 2011–12 and Household Wealth and Wealth Distribution, Australia, 2011–12 products. The publication presents key information about household income and wealth from the 2013–14 SIH. The primary benefit of integrating the Income and Wealth publications is to allow for income and wealth to be considered together when analysing household economic resources. This approach enables more accurate representation of household economic wellbeing.

Geography

In 2011 the Australian Statistical Geography Standard (ASGS) was published to replace the former geography framework, the Australian Standard Geographical Classification (ASGC). The 2013–14 SIH data is presented on the current ASGS. Data from prior cycles uses the ASGC classification.

For further information on ASGS refer to the publication Australian Statistical Geography Standard (ASGS): Volume 1 - Main Structure and Greater Capital City Statistical Areas, July 2011 and http://www.abs.gov.au/geography.

Government pensions and allowances

Lump sum Government payments included in SIH 2013–14 are the Dad and Partner Pay, the Clean Energy Supplement (CES) and the School Kids Bonus.

Dad and Partner Pay is a new entitlement under the Paid Parental Leave Scheme paid directly to a working dad or partner who cares for a child born or adopted from 1 January 2013. Dad and Partner Pay gives you up to two weeks of government-funded pay at the rate of the National Minimum Wage. The Dad and Partner Pay can be taken all at once at any time in the first year after birth or adoption.

The Clean Energy Supplement (CES) replaced the Clean Energy Advance (CEA) from March 2013 and was captured for the 2013–14 SIH. The Clean Energy Supplement provided an increase on the standard Age Pension rate and was paid in addition to existing Pension Supplements.

The School Kids Bonus replaced the Education Tax Refund from January 2013 and was captured for the 2013–14 SIH. School Kids Bonus is made payable to families receiving Family Tax Benefit Part A, young people in school receiving Youth Allowance and some other income support and veterans payments who met age and education requirements.

Tax payable/Dividends

The collection of dividends was changed for this cycle. In previous cycles, respondents were asked to report their dividend income including the franking credit. In 2013–14, dividend income for publicly listed shares was collected excluding franking credits. These were imputed and added to total dividend income using the most recent ATO data on the proportion of franked and unfranked dividends. Previously an adjustment for the under-reporting of franking credits was applied to the income tax model so that while gross income from dividends was understated, disposable income was not affected.

The 2011–12 SIH content was largely similar to the 2009–10 SIH with some changes in questions, definitions and methodology. Key changes to the 2011–12 SIH include:

• a decrease in fully responding sample size from 18,071 households in 2009–10 to 14,569 households in 2011–12. The expansion in the 2009–10 sample for an extra 4,200 households outside capital cities to support housing indicator reporting was maintained. The additional sample of metropolitan households whose main source of income was a government pension, benefit and/or allowance included in the 2009–10 SIH and HES samples to improve analysis for the Pensioner and Beneficiary Living Cost Index was not maintained
• an additional benchmark for the value of government benefit cash transfers used in 2009–10 was not required in 2011–12
• disability questions for persons aged 15 years and over were not asked in 2011–12, but will be collected in 2013–14
• Child Care Rebate (CCR) and Child Care Benefit (CCB) have been modelled to improve estimates of both the payment amounts and the number of households receiving assistance
• the value of offset accounts was collected separately for the first time
• selected social transfers in kind variables have been modelled in 2011–12, and analysis included in the publication Household Income and Income Distribution, Australia, 2011–12
• a feature article on Low Economic Resource households is included in the publication Household Income and Income Distribution, Australia, 2011–12.

The expansion in the 2009–10 sample for an extra 4,200 households was maintained in the 2011–12 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.

The additional sample of metropolitan households whose main source of income was a government pension, benefit and/or allowance included in the 2009–10 SIH and HES samples has not been maintained in the 2011–12 sample. The main purpose of this additional sample was to support improved analysis for the Pensioner and Beneficiary Living Cost Index (PBLCI).

Changes to Government pensions and allowances

Paid Parental Leave (PPL) was introduced on 1 January 2011 as an alternative to the Baby Bonus. Under the Paid Parental Leave scheme, eligible working parents can get government funded pay when they take time off from work to care for a newborn or recently adopted child. The income test for PPL requires that the parent or parents earn no more than $150,000 in the year previous to the child's birth. People who meet the eligibility requirements must decide which payment, paid parental leave or Baby Bonus, is best suited to them, as both payments cannot be received for the same child.

One off Government payments included in SIH 2011–12 are the Clean Energy Advance and the one-off Education tax refund.

The Clean Energy Advance payment is a tax-exempt lump sum payment, paid in May and June 2012 to help low and middle income households meet the impacts of carbon pricing on living expenses for up to 12 months. This is a one-off payment paid to pensioners, other income support recipients, families receiving Family Tax Benefit payments and Seniors Supplement recipients, provided they met eligibility requirements.

One-off Education Tax Refund payments were paid in June 2012 as part of the transition to the new School kids Bonus and in place of the Education Tax Refund for the 2011–12 financial year. The one-off payment was made payable to families receiving Family Tax Benefit Part A, plus young people in school receiving Youth Allowance and some other income support and veterans payments, providing they met age and education requirements. The Schoolkids Bonus replaces the Education Tax Refund from January 2013.

Other changes

Errors in processing the 2009–10 income data have been corrected, resulting in an average decrease of $1 for mean equivalised disposable household income across all households. This was reflected largely in a decrease of 0.04% in the mean equivalised disposable household income of households in the second and third deciles. The income estimates for 2009–10 shown in this publication have been revised. The second edition of the 2009–10 CURF includes the revised estimates.

The 2009–10 SIH content was largely similar to the 2007–08 SIH with some changes in questions, definitions and methodology. Key changes to the collection include:

• an increase in the sample size from 9,345 households in 2007–08 to 18,071 households in 2009–10 due to a 10,800 base sample, an expansion in the SIH sample for an extra 4,200 households, located outside capital cities as well as an additional sample of metropolitan households whose main source of income was a government pension, benefit and/or allowance
• the inclusion of a benchmark for the value of government benefit cash transfers to ensure that the survey estimate of government benefit cash transfers is maintained at a proportion of aggregate benefit cash transfers that is consistent with previous SIH cycles (this benchmark was last used in the 2000–01 SIH)
• housing data on dwelling condition, characteristics, mobility, finance and rental arrangements collected in 2007–08 were not collected in 2009–10
• wealth data items on assets and liabilities were collected in 2009–10 (last collected in 2005–06 SIH)
• disability questions were asked for persons aged 15 years and over in the 2009–10 SIH
• improvements, aligning with international statistical standards, to the collection of income statistics including to:
  • incorporate non-cash benefits provided to employees;
  • incorporate termination payments and lump sum workers' compensation payments; and
  • improve the coverage of bonuses and irregular overtime payments and inter-household transfers. For more information see Appendix 4 of Household Income and Income Distribution, Australia, 2007–08.
• improvements to the collection of the value of assets in public unit trusts and private trusts.

The 2009–10 HES content was largely similar to the 2003–04 HES with some changes in questions, definitions and methodology. Key changes to the collection include:

• an increase in the sample size from 6,957 households in 2003–04 to 9,774 households in 2009–10 due to the inclusion of an additional sample of metropolitan households whose main source of income was a government pension, benefit and/or allowance
• improvements, aligning with international statistical standards to the collection of income statistics
• the incorporation of non-cash benefits used by employees to improve the coverage of consumption expenditure and to ensure consistency with the conceptual treatment of income
• a small number of changes to some Household Expenditure Classification (HEC) categories, particularly to address emerging technologies between the survey cycles. For details see Appendix 6 of the Household Expenditure Survey and Survey of Income and Housing, User Guide, Australia, 2009-10 User Guide (cat. no. 6503.0).
• disability questions for persons aged 15 and over were asked in the 2009–10 HES (last collected in HES in 1998–99)
• the inclusion of expenditure classified by the Classification of Individual Consumption According to Purpose (COICOP) for the first time.

The May 2009 Budget funded an expansion in the SIH sample for an extra 4,200 households, primarily located outside capital cities. This expansion was to better support Council of Australian Governments (COAG) performance indicator reporting, particularly in regard to housing affordability and home ownership measures required under COAG intergovernmental agreements.

For the 2009–10 SIH and HES there was also an additional sample of metropolitan households whose main source of income was a government pension, benefit and/or allowance. These pensioner sample households were enumerated using a separate sample design, but the fully responding in scope households from this sample were included in the final SIH samples.

In addition to the changes already listed for 2009–10, there were also a number of changes that related to specific data items.

Income measures

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 2007–08 and 2009–10 income estimates for the SIH and the HES apply the new income standards. Information about ABS' improved household income measures, is available in Part 4.2 'Changes in the 2007–08 SIH User guide' (cat. no. 6553.0).

As these standards have now been implemented for more than the 2007–08 cycle in which they were introduced, current income items have had some label changes.

• In 2007–08, they were labelled as '2007–08 basis' items to be clearly identified from '2005–06 basis' and earlier items used prior to the introduction of the new standards. From 2009–10, all income items using the current income standard now have no qualifier in the label, as they no longer apply to a specific survey cycle. For example, the item 'Total current weekly income from all sources (2007–08 basis)' is now 'Total current weekly income from all sources'.
• Income items about the 'Principal source of income' are now labelled 'Main source of income', consistent with the new standards.

Other Changes

There have been changes to some pensions and allowances paid by the government, resulting in both the deletion of items and the addition of new items. This is consistent with previous cycles, where changes to government pensions and allowances made since the last survey cycle are implemented. In the 2009–10 SIH, particular changes in government pensions and allowances resulted in new modelled items and changes in populations. The introduction of the Pension Supplement and the Seniors Supplement on 20 September 2009 was a significant change, and occurred while the 2009–10 SIH was in the field. As a result, the Pension Supplement and Seniors Supplement were modelled from data collected from respondents based on their reported payments and eligibility. The Utilities Allowance now forms part of these supplements for some recipients, but is still paid separately to recipients of some pension and allowance recipients. As a result, comparisons with data from 2007–08 and earlier are not possible for affected items, as eligible populations have changed in addition to payment types.

Errors in processing the 2007–08 income estimates have been corrected, resulting in an average increase of $3 for mean equivalised disposable household income across all households. This was reflected largely in a 1.3% increase in the mean equivalised disposable household income of households in the highest quintile. The income estimates for 2007–08 shown in this publication have been revised.

The 2007–08 SIH was largely similar to the 2005–06 SIH, but there were some changes in topics, definitions and methodology. The main changes that could impact on all data items were:

• the final sample size of the SIH, which decreased from 9,961 in 2005–06 to 9,345 in 2007–08
• benchmarks based on the 2006 Census were used for the 2007–08 SIH; in 2005–06 benchmarks were based on the 2001 Census
• more detailed age benchmarks were used when determining the weights to be allocated to each unit in 2007–08 estimates
• the imputation procedures were changed: in 2007–08, as in 2003–04, all households where one or more people did not respond were imputed if the non–responding person was not a 'significant' person; in 2005–06, all households where one or more people did not respond were treated as non-responding.

There were also a number of changes that related to specific data items.

Improvements to income measures

The ABS undertook a major review of its income standards, to ensure that its standards and practices appropriately reflected new international standards for household income statistics (promulgated in 2004) and suitably addressed a range of outstanding methodological and collection issues. The 2007–08 SIH income estimates were the first to apply the changes.

The income measures used in the 2007–08 SIH included changes to employment income, investment income, lump sum payments and financial support. Specific changes in the income measures used in the 2007–08 survey were:

• Employment income included all payments received by individuals as a result of their current or former involvement in paid employment. In addition to the regular and recurring cash receipts previously included, the new income measures also included non-cash benefits, bonuses, termination payments and payments for irregular overtime.
• Interest paid on money borrowed to purchase shares or units in trusts was netted off income earned from these sources when deriving income estimates.
• Income earned as a silent partner in a partnership and some private trust income was classified to investment income rather than unincorporated business income. This change did not affect trust income resulting from the recipient working in their own business, which continued to be classified as unincorporated business income. The questions developed to effect this change also improved the reporting of income from these sources.
• Lump sum workers' compensation receipts were included.
• A wider range of data on financial support received from family members resident outside the household was included. In addition to regular payments previously collected, financial support was extended to include other forms of financial support, including goods and services received which were purchased by others, e.g. rent, education, food, clothing, car registration and utilities. Capital transfers, such as the purchase of property or cars, were excluded.

Some limits were placed on the new inclusions where the magnitude of the individual amounts received exceed that likely to be used to support current consumption, e.g. termination payments and workers' compensation payments. For more information see 'Appendix 4 Improvements to income statistics' of the publication Information Paper: Survey of Income and Housing, User Guide, Australia, 2007–08 for more information on the changes to income measures.

Inclusion of child care data

There were additional questions on the use of child care, including preschool for a selected child, covering: type; time used; costs; and Child Care Benefit (CCB) received. In addition there were new data items on barriers to labour force participation due to child care related reasons. For more information see 'Part 1 Concepts and definitions' of the publication Information Paper: Survey of Income and Housing, User Guide, Australia, 2007–08.

Inclusion of additional housing data

The 2007–08 SIH included additional housing topics to enable reporting on the broader housing circumstances of non-Indigenous Australians. The ABS will collect additional information on housing in the SIH every six years. For the 2007–08 SIH, housing topics included housing mobility, housing condition and dwelling characteristics, home purchase for first home buyers, household finances of owners with a mortgage, rental arrangements and the affairs of renters, and neighbourhood. For more information see 'Appendix 6 Additional housing topics, 2007–08' of the publication Information Paper: Survey of Income and Housing, User Guide, Australia, 2007–08.

Inclusion of data on ethnicity

There were additional questions relating to country of birth of each parent, first language spoken, main language spoken at home, and proficiency in spoken English.

Changes to financial support received from or provided to family members not in the household

In the 2007–08 SIH, a wider range of data on financial support received from and paid to family members resident outside the household was collected. Previously these were mainly limited to regular payments for spousal maintenance and child support. In 2007–08, respondents were asked to include other forms of financial support, including goods and services received which were purchased by others, e.g. rent, education, food, clothing, car registration and utilities. Capital transfers, such as for the purchase of property or cars, were excluded.

Inclusion of data on tenure type for income units and persons

The 2007–08 SIH collected information on the tenure and landlord type for income units and persons. New data items were included at the person level relating to tenure, landlord type and weekly rent payments. New data items were also included at the income unit level relating to tenure and landlord type. The information was previously available from the 2002–03 SIH.

Improvement in selection of household reference person

Improvements were made in the way the household reference person was identified in the 2007–08 SIH. In the 2005–06 SIH, the household reference person was identified by applying selection criteria about relationships, income and age. However, this method did not always identify the correct reference person, particularly for some group households (where one person may be the owner and other unrelated individuals are also living in the dwelling) or first home buyers (where the first home buyer may not be selected as the household reference person based simply on relationship income and age). In the 2007–08 SIH, tenure was added as a criterion in determining the household reference person. For more detailed information about the selection criteria used to identify the household reference person see the 'Glossary' section of this publication.

Commonwealth Rent Assistance (CRA)

New data items were included at the income unit and person levels relating to the receipt of CRA and the amount received. CRA is a non-taxable income supplement paid through Centrelink to individuals and families who rent in the private rental market. It is only paid to recipients of another government benefit or pension, and is paid in conjunction with that other payment. Reported amounts of CRA were added to the relevant reported benefit or pension during processing where it was identified that the amount had not been included.

Loans level data

The 2005–06 SIH CURFs contained housing cost data items at the household level relating to the amounts owing on mortgages and unsecured loans for housing and other purposes. The 2007–08 SIH CURFs also contained those data items, but also included a new loans level that contained data items relating to each reported loan belonging to a household.

Other changes

Some changes were implemented within the derivation process to correct errors detected when calculating the disposable income for some households in receipt of tax offsets. Estimates for the 2005–06 SIH were updated and reflected in the 2007–08 publication.

The 2005–06 SIH was largely similar to the 2003–04 SIH, but there were some changes in topics, definitions and methodology. The main changes that could impact on all data items were:

• the 2003–04 SIH was integrated with the HES whereas the 2005–06 survey was run as a stand-alone survey
• the final sample size decreased from 11,361 household in 2003–04 to 9,961 in 2005–06
• the scope of the survey was changed slightly. In the 2003–04 SIH, all people living in Indigenous communities were out of scope; in the 2005–06 SIH they were out of scope only if they were living in Very Remote areas
• the benchmarks used were based on the 2001 Census, and these benchmarks were consistent with the scope of the survey in that people living in Very Remote areas in all states and territories were excluded. In the 2003–04 SIH, the benchmarks used were based on the 1996 Census and did not exclude people living in Very Remote areas, except in the Northern Territory where people living in areas defined as sparse were excluded
• more detailed age benchmarks were used when determining the weights to be allocated to each unit in the 2005–06 SIH estimates
• imputation procedures were changed - all households where one or more people did not respond were treated as non-responding; in the 2003–04 SIH these were imputed if the non-responding person was not a 'significant' person.

There were also a number of changes that related to specific data items.

Inclusion of all salary sacrificed income

In the published output from the 2005–06 SIH, all amounts salary sacrificed were included in wages and salary estimates. In output from previous surveys, estimates included only some salary sacrificed amounts. The 2003–04 SIH estimates published in the 2005–06 issue of Household Income and Income Distribution, Australia, 2005–06 were revised to include additional salary sacrificed amounts. The changed treatment of salary sacrifice did not impact significantly on the estimates. In the 2005–06 SIH the Gini coefficient calculated on the new basis was 0.307, compared with 0.304 when compiled on the former basis. Including all salary sacrifice in the income estimates for the 2005–06 SIH added 0.003 points to the Gini coefficient and $5 (0.8%) to mean weekly equivalised disposable household income.

Improvements to Family Tax Benefit (FTB) estimates

Improvements were made to estimates relating to current income from the FTB. Prior to the 2005–06 SIH, the FTB item only included FTB received as fortnightly payments. FTB paid through the tax system or as a lump sum was excluded for practical reasons. The items 'Total current weekly income from government pensions and allowances' and 'Total income from all sources' also excluded these components, but they were included in measures of disposable income. In the 2005–06 SIH the new FTB item 'Current weekly income from family tax benefits (modelled)' included all FTB payments, regardless of whether they were received fortnightly, via the tax system or as a lump sum. It also included payments of FTB supplement. Some components of the FTB item used in the 2005–06 SIH were modelled using information on income and household demographics reported in the survey. All income aggregates included the new item. It should be noted that there was little impact on comparability of estimates of disposable income as a result of the change, since disposable income has always included modelled components relating to FTB paid through the tax system or as a lump sum.

Housing costs definition

The housing costs measure used in the 2005–06 issue of Housing Occupancy and Costs, Australia, 2005–06 was slightly different from the measure used in prior issues. In prior issues housing costs comprised: rates payments for owners; rates and housing loan payments for owners with a mortgage; and rent payments for renters. In 2005–06, information on housing costs for other tenure types, which was first collected in the 2003–04 survey, was included. The definition of housing costs was no longer dependent on tenure: it was defined as the sum of rent payments; rates payments; and mortgage or unsecured loan payments if the initial purpose was primarily to buy, add to, or alter the dwelling. The revised definition added only about $1 (less than 1%) to mean weekly housing costs.

Other changes

There were changes to some pensions and allowances paid by the government, resulting in new items for maternity payment, utilities allowance, seniors concession allowance and one-off payments to older Australians.

A number of changes were made to the derivation process used to estimate income tax liability. In prior surveys estimates of imputed tax payable included an adjustment to subtract estimated FTB payments made through the tax system or as a lump sum. This ensured that FTB payments made through the tax system or as a lump sum were included in disposable income. This adjustment was no longer required since such payments were included in the gross income estimates in 2005–06.

The 2003–04 SIH was integrated with the 2003–04 HES. This integration was achieved by selecting a subsample of the households in the SIH survey and asking them the additional questions required for HES purposes. The HES subsample comprised 6,957 of the 11,361 households responding to the SIH. The main advantages of integrating the surveys were:

• respondent burden is lower
• the data collection costs are lower
• the resultant dataset is a richer suite of data because HES and SIH results are more comparable than data obtained prior to 2003–04.

However, in order to achieve this integration, some changes were required to both surveys which impact on comparability with previous surveys. In addition, it is possible that the integration of the surveys affected the non-response bias in the SIH. The response rates for the HES subsample are lower than achieved in the SIH-only sample component because of the reluctance of some respondents to provide the extra information required in the HES part of the survey. The non respondents to the 2003–04 survey may therefore have different characteristics to the non respondents of previous SIHs, resulting in different non-response bias.

A few data items collected in previous surveys were not collected in the 2003–04 SIH. These include:

• income unit level tenure – in 2003–04 tenure was available at the household level only
• labour force status in each of the 7 months prior to the interview
• full-time/part-time status in each of the 7 months prior to the interview
• month left school.

In previous SIHs, the household reference person was chosen from an income unit within the household that had the highest tenure type. Tenure type was collected for households but not for income units in the 2003–04 SIH. The tenure type of income units was therefore not used in determining which person in the household is to be designated as household reference person.

In the published output from the surveys, the data item "family composition of household" replaced the item "household composition". The new item better met user requirements for the treatment of households with dependent children.

There were a number of changes to the survey methodology introduced in 2003–04. Some of these were a consequence of the integration of the SIH and HES.

The main changes which could impact on all data items were:

• previous SIH cycles had selected dwellings from those that had been respondents for eight months in the Monthly Population Survey (MPS), whereas in 2003–04 the SIH sample was drawn from dwellings not recently included in an ABS household survey (possible change in response bias)
• the sample size of the SIH was increased from 10,211 households (comprising 19,400 persons aged 15 and over) in 2002–03 to 11,361 households (comprising 22,315 persons aged 15 and over) in 2003–04 (lower sample error)
• interviewer use of a laptop computer (this may have improved data capture)
• editing and imputation procedures were changed - in particular because the SIH sample was no longer drawn from households who had participated in the MPS, responses given in the MPS were no longer available as a basis for imputation.

The changes in survey methodology relating to specific data items were:

• current income from own unincorporated business and investments was measured using respondents' estimates of expected income in the current financial year, whereas previously these data items were estimated based only on information about reported income for the previous financial year - this change had a significant impact on the coverage of such income streams in current income measures
• the collection of details about the assets and liabilities of the household may have improved the quality of reporting of associated income streams
• the instrument wording was changed to explicitly ask that reported dividends include the value of imputation credits - previously this direction was only included in interviewer instructions
• information relating to some household loans was collected using a different methodology - for those loan accounts that have a redraw facility and have regular income (such as wages) deposited into them, respondents were not asked to provide a 'usual repayment' - instead they were asked to provide the amount that the principal outstanding usually decreases by, in a 6 month period, and this was used in conjunction with information collected on interest to derive a repayment amount
• details of previous financial year income were collected from all persons - in previous SIHs this information was not collected from people who had only arrived in Australia in the current financial year
• details of hours worked were collected from all employed persons - in previous SIHs, this information was only available for employees
• unlike previous SIHs, data on repayments and principal outstanding on mortgages for other purposes (i.e. for purposes other than building, buying, altering or adding to the selected dwelling) excludes mortgages that were used for business or investment purposes.

The SIH cycles from 1994–95 to 2002–03 are comparable. These files were reprocessed in 2003 to apply consistent demographic benchmarks to all years and to incorporate the latest demographic estimates in the benchmarks. Changes over this period are generally minor and are summarised below:

• the sample size was fairly constant at about 7,000 households from 1994–95 to 2000–01, but increased to 10,211 in 2002–03
• an extra benchmark was used in the weighting process in 1999–2000 and 2000–01 to compensate for an apparent fall in the coverage of government benefit payments in those years
• any changes to government pensions and allowances were incorporated
• the introduction of new standards, (e.g. the introduction of the Australian Standard Classification of Occupations (ASCO), Second Edition, 1997 in the 1996–97 SIH).

In addition, the item, 'Nature of occupancy ' was replaced by 'Tenure type' from 1995–96. Prior to 1995–96 owner occupiers were classified as either owners or purchasers. A purchaser had a mortgage or loan secured against the dwelling, and the loan was used to purchase or build the dwelling. An owner had no loan secured against the dwelling for the purpose of building or purchasing. From 1995–96, owner occupiers were classified as owners without a mortgage and owners with a mortgage. This change to the classification was made to reflect the increasing diversity in financial instruments, in particular the increasing use of loans secured against dwellings being used for non-housing purposes. Such secured loans have implications for the security of tenure and a household with such a loan is classified as an owner with a mortgage in the new classification.

Previous surveys of household income were conducted by the Australian Bureau of Statistics (ABS) in 1979, 1982, 1986 and 1990. These surveys were generally conducted over a two-month period, compared to a twelve-month period for the SIH. The SIH also included improvements to the survey weighting and estimation procedures, changes to the scope and coverage of household income and changes to interviewing methods.

Previous Household Expenditure Surveys were conducted by the Australian Bureau of Statistics (ABS) in 1974–75, 1975–76, 1984, 1988–89, 1993–94, 1998–99, however, current results are only comparable back to 1984 when the Household Expenditure classification (HEC) was first introduced.