CHANGES IN THE 2005-06 SIH
The 2005-06 SIH was similar to the 2003-04 SIH, but there were some changes in definitions and methodology.
CHANGES IMPACTING ON ALL DATA ITEMS
The main changes which could impact on all data items were:
- the 2003-04 SIH was integrated with the Household Expenditure Survey while the 2005-06 SIH was run as a stand alone survey
- the final sample size decreased from 11,361 households in 2003-04 to 9,961 in 2005-06
- the scope of the survey was changed slightly - in 2003-04, all people living in Indigenous communities were out of scope; in 2005-06 they were out of scope only if they were living in very remote areas
- benchmarks based on the 2001 Census have been used, and the benchmarks are consistent with the scope in that people living in very remote areas in all states and territories are excluded; in 2003-04, benchmarks 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 2005-06 estimates; for further information see Section 2.6
- imputation procedures were changed - all households where one or more people did not respond were treated as non-responding; in 2003-04 these were imputed if the non-responding person was not a 'significant' person.
CHANGES RELATING TO SPECIFIC DATA ITEMS
There were also a number of changes that relate to specific data items.
Inclusion of all salary sacrificed income
In the published output from the 2005-06 survey, all amounts salary sacrificed have been included in wages and salary estimates. In output from previous surveys, estimates have included only some salary sacrificed amounts. The 2003-04 estimates published in the 2005-06 issue of Household Income and Income Distribution, Australia (cat. no. 6523.0) have also been revised to include additional salary sacrificed amounts. The changed treatment of salary sacrifice has not impacted significantly on the estimates. In 2005-06 the Gini coefficient on the new method was 0.307, compared with 0.304 when compiled on the former method. Including all salary sacrifice in the income estimates for 2005-06 has added 0.003 points to the Gini coefficient and $5 (0.8%) to mean weekly equivalised disposable household income.
Income items produced using the former method are available to assist users who wish to analyse data that is comparable to previously published data. In these items, only those salary sacrificed amounts that had been reported by respondents as cash income were included in wages and salary estimates.
For further information on the changed treatment of salary sacrifice, see Appendix 4.
Improvements to family tax benefit estimates
Improvements have been made to estimates relating to current income from family tax benefit (FTB). Prior to 2005-06, 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 2005-06 the new FTB item 'Current weekly income from family tax benefits (modelled)' includes all FTB payments, regardless of whether they are received fortnightly, via the tax system or as a lump sum. It also includes payments of FTB supplement. Some components of the new item are modelled using information on income and household demographics reported in the survey. All income aggregates include the new item. It should be noted that there is little impact on comparability of estimates of disposable income as a result of this 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 (cat. no. 4130.0.55.001) is 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 is included. The definition of housing costs is no longer dependent on tenure - it is defined as the sum of rent payments, rates payments, and mortgage or unsecured loan payments if the initial purpose was primarily to buy, add or alter the dwelling. The revised definition adds only about $1 (less than 1%) to mean weekly housing costs.
There have been 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 payment to older Australians.
A number of changes have been 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 is no longer required since such payments are included in gross income estimates.