EXPLANATORY NOTES
INTRODUCTION
1 This publication presents the housing costs and characteristics of households and persons resident in private dwellings in Australia, compiled from the 2003-04 and earlier Surveys of Income and Housing (SIH), previously known as the Survey of Income and Housing Costs. The survey collected information on sources of income, amounts received, housing costs and characteristics of persons aged 15 years and over resident in private dwellings throughout non-sparsely settled areas of Australia.
2 The SIH was conducted continuously from 1994-95 to 1997-98, and then in 1999-2000, 2000-01, 2002-03 and 2003-04. The 2003-04 SIH included an expanded sample of approximately 11,000 households, which were enumerated from July 2003 to June 2004. In future, the SIH will be conducted every second year.
3 Other collections conducted by the Australian Bureau of Statistics (ABS) which covered housing were:
- Survey of Health Conditions, the Aged and Housing, 1988
- Survey of Income and Housing Costs and Amenities, 1990
- Australian Housing Survey, 1994 and 1999
- Census of Population and Housing, 2001.
4 Care should be taken when comparing data from the different sources due to the different methodologies used in these surveys.
5 The 2000-01 SIH introduced a range of methodological and presentational changes primarily aimed at improving the measurement of changes in income distribution. Details are available in Household Income and Income Distribution, Australia, 2000-01, (cat. no. 6523.0).
Changes in this issue
6 A number of major changes designed to improve survey quality have been introduced in the 2003-04 SIH. In some cases the changes may impact on the comparability between the 2003-04 estimates and earlier data, but it is generally not possible to quantify the extent of any discontinuity. Changes expected to have improved the quality of the data include:
- a larger sample of 11,361 households (comprising 22,315 persons aged 15 and over) for 2003-04 compared to 10,211 households (comprising 19,400 persons aged 15 and over) for 2002-03 (lower sample error)
- previous SIH cycles had selected dwellings from those that had been respondents for eight months in the monthly population survey (MPS), whereas from 2003-04 the SIH sample is drawn from dwellings not recently included in an ABS household survey (possible change in response bias)
- interviewer use of a laptop computer instead of a paper form to collect information from respondents (possible improvement in data capture)
- an expanded range of questions to collect details about income - in particular, information was collected about expected income in the current financial year from own unincorporated business and investments, whereas previous "current period" estimates for these components of income were set based only on information about reported income for the previous financial year (a significant impact on the coverage of such income streams in current income measures)
- a comprehensive range of questions to collect details about the assets and liabilities of the household, which may have improved the quality of reporting of associated income streams.
7 The 2003-04 SIH has been integrated with the 2003-04 HES. This integration has been achieved by selecting a subsample of the households in the SIH survey and asking them the additional questions required for HES purposes. Respondent burden is lower than if the two surveys were not integrated. Also, the resultant dataset is richer because HES and SIH results are more comparable than previously. However, response rates for the HES subsample are lower than achieved in the 2003-04 SIH-only sample component because of the reluctance of some respondents to provide the extra information required in the HES part of the survey. It is therefore possible that the differing reasons for non-response in the 2003-04 SIH result in different biases to those resulting from non-response when the SIH was conducted in conjunction with the MPS.
8 In previous SIHs, the household reference person was chosen from an income unit within the household that had the highest tenure type. Tenure type has been collected for households but not for income units in the 2003-04 SIH. The tenure type of income units is therefore no longer used in determining which person in the household is to be designated as household reference person.
9 The methodology of the 2003-04 SIH, including the collection of household asset and liability information, is being retained for the 2005-06 SIH, except that there will be no HES subsample in 2005-06. The next HES subsample will be included in 2009-10.
10 Changes in the contents of this issue are:
- the inclusion of state and balance of state data for selected tables
- the replacement of the data item "household composition" with the data item "family composition of household", which better meets user requirements for the treatment of households with dependent children.
CONCEPTS AND DEFINITIONS
11 The concepts and definitions relating to statistics of housing costs are described in the following section. Other definitions are included in the Glossary.
Household
12 The household is the basic unit of analysis in this publication. This may be: a group of two or more persons living in the same dwelling, who make common provision for food or other essentials for living, or one person who makes provision for his/her own food or other essentials for living without combining with any other person. A group of people who make common provision for living essentials but are living in two separate dwellings are considered to be two separate households.
13 The use of the household as the basic unit of analysis in this publication requires that the estimates of income and housing costs are based on the sum of the income and housing costs of all household members. Intra-household transfers, however, are excluded. For example, if one member of the household were to pay board to another member of the same household then this is not considered as an increase in the amount of income or housing costs of the household. If such transfers were to be included there would be double counting.
Housing costs
14 Housing costs are the recurrent outlays by household members in providing for their shelter. The data collected on housing outlays in the SIH are limited to major cash outlays on housing, that is, mortgage repayments and property rates for owners, and rent. Mortgage, rent and rates payments are shown in this publication as weekly equivalents.
15 Only payments which relate to the dwelling occupied by the household at time of interview, that is, a respondent's usual place of residence, are included. Housing costs only include mortgage/loan payments if the purpose of the loan at the time it was initially taken out was primarily to buy, build, add to or alter the occupied dwelling.
16 There are a number of limitations to the housing costs information obtained in the SIH, due to practical data collection considerations. These limitations should be especially borne in mind when comparing the housing costs of different tenure and landlord types, that is, when comparing the costs of owner occupiers with the costs of renting households, and when comparing the costs of households renting from state and territory housing authorities with the costs of other renters.
- Households are sometimes reimbursed some or all of their housing costs, but these reimbursements are not collected in the SIH. Commonwealth Rent Assistance (CRA), paid by the Australian Government to qualifying recipients of income support payments and family tax benefit, is the most important type of reimbursement of relevance to these statistics. Attempts to reliably collect this information in a household survey have not been successful. If rent assistance receipts were subtracted from gross housing costs, the housing costs of households receiving rent assistance are estimated to be about 30% lower on average, and the housing costs of all households renting from landlords other than the state/territory authorities would be about 10% lower on average.
- Mortgage repayments made by owners with a mortgage include both the interest component and the principal or capital component. For many purposes it is more appropriate to consider repayments of principal as a form of saving rather than as a recurrent housing cost. It reflects the purchase of a housing asset by increasing the equity in the property held by the household and is an addition to the wealth of the occupants. The 2003-04 SIH indicates that about 40% of the housing costs of owners with a mortgage, as derived for this publication, comprised repayments of the principal on loans. However, this split of loan repayments is not available from previous SIHs.
- A fuller measure of housing costs would include a range of outlays not collected in the SIH, but which are necessary to ensure that the dwelling can continue to provide an appropriate level of housing services. These include repairs, maintenance, body corporate fees and dwelling insurance, and are costs that tend to be incurred by owner occupier households but not by renting households. HES data shows that if these costs were added to SIH housing costs estimates, the estimates of average housing costs in this publication would be more than doubled for owners without a mortgage and would increase by about 15% for owners with a mortgage. (Appendix 1 outlines differences between the housing costs estimates available from the SIH and the HES. Paragraph 70 provides references for the HES.)
Housing costs and household income
17 Housing costs can be a major component of total living costs. Therefore housing costs are often analysed as a proportion of total income, sometimes referred to as affordability ratios, and this publication presents a variety of housing cost/income ratio measures. However, comparisons between these measures are subject to the limitations of housing cost estimates obtained in the SIH that are described in the previous paragraph. Housing affordability ratios derived from SIH data are further impacted by the inclusion of CRA in the value of income collected. CRA is estimated, on average, to represent about 8% of the reported income of households receiving CRA and nearly 2% of the reported income of all households renting from landlords other than the state/territory authorities.
18 To illustrate the difficulties discussed above, consider two households that are renting their dwellings. Both receive government pensions of $400 per week. One rents from a public housing authority and pays rent of $100 per week. The other pays $135 rent per week to a private landlord and receives Commonwealth Rent Assistance of $35. In SIH, the housing costs of the latter household would be recorded as $135 and their income would be recorded as $435. The couple renting from the public housing authority has a housing costs/income ratio of 25%. The housing costs/income ratio for the latter household would be derived as 31%. If CRA receipts are excluded from housing costs and income the housing costs/income ratio for the latter couple is also 25%, highlighting that there is no substantive difference between the housing costs or income situation of the two couples. This anomaly is of particular concern when considering changes in affordability ratios over time, since there has been a shift from providing public housing to providing CRA as a means of supplying affordable housing to low income people.
19 While housing costs can be a major component of total living costs, the difference between the housing costs of a larger household and a smaller household would not be expected to be as great as the difference in many other costs, such as food or clothing. In other words, larger households can be expected to experience economies of scale in the supply of housing. This means that if a larger household and smaller household both have the same standard of living, it could be expected that on average the larger household will have a lower housing costs/income ratio. Therefore relatively high housing costs/income ratios are more of a concern with respect to larger households than smaller households. This should be borne in mind when comparing ratios across different household sizes.
20 In comparing households' housing costs with their income, it should be borne in mind that households have a variety of housing preferences. Some people may choose to live in an area with high land values because it is close to their place of employment and therefore they have lower transport costs. Some people choose to incur relatively high housing costs because they prefer a relatively high standard of housing instead of other consumption possibilities. High mortgage repayments might reflect a choice to purchase a relatively expensive home, or pay off a mortgage relatively rapidly, as a form of investment.
Housing stress
21 Households with relatively low income and housing costs greater than a certain proportion of income, often 30%, are sometimes said to be in "housing stress". This publication has not included such measures because of the lack of comparability of the housing affordability ratios across tenure and landlord types, and the difficulties of comparing across different household sizes, as described in the previous paragraphs. However, table 5 does provide information separately for lower income households. As explained in paragraph 33 below, the incomes of many of the people falling into the lowest decile are not an appropriate indicator of the economic resources available to them. Lower income households are therefore defined here as those with incomes between the bottom 10% and bottom 40% of the distribution of equivalised disposable household income.
Housing utilisation
22 The concept of housing utilisation in this publication is based upon a comparison of the number of bedrooms in a dwelling with a series of household demographics such as the number of usual residents, their relationship to one another, age and sex. There is no single standard of measure for housing utilisation. However the Canadian National Occupancy Standard presented in this publication is widely used internationally.
23 The Canadian National Occupancy Standard for housing appropriateness is sensitive to both household size and composition. The measure assesses the bedroom requirements of a household by specifying that:
- there should be no more than two persons per bedroom
- children less than 5 years of age of different sexes may reasonably share a bedroom
- children less than 18 years of age and of the same sex may reasonably share a bedroom
- single household members 18 over should have a separate bedroom, as should parents or couples.
24 Households living in dwellings where this standard cannot be met are considered to be overcrowded.
Tenure type and landlord type
25 The concept of housing tenure is based on the type of legal right of the occupant to occupy the dwelling. Tenure is determined according to whether the household owns the dwelling outright, owns the dwelling but has a mortgage or loan secured against it, is paying rent to live in the dwelling or has some other arrangement to occupy the dwelling.
26 Owners are divided into two categories - owners with mortgages and owners without mortgages. A household's tenure type is owner with a mortgage if there is any outstanding mortgage or loan secured against the dwelling. This mortgage or loan may have been initially obtained primarily for either the purchase or the building of the dwelling, or for undertaking alterations or additions, or for some other purpose such as the purchase of a vehicle or an investment property. However, mortgage payments where the initial purpose of the loan was not primarily for housing are not treated as housing costs. A household's tenure type is owner without a mortgage if there are no loans or mortgages secured against the dwelling.
27 Renters are occupants who pay money as rent to another person or organisation, referred to as the landlord, in return for being allowed to occupy the dwelling. Renters can be further classified according to type of landlord. The landlord may be a relative or an unrelated person in another dwelling or can be a real estate agency, a state or territory housing authority, a community organisation, a trust, or an employer.
Income
28 Income refers to regular and recurring cash receipts from employment, investments and transfers from government, private institutions and other households. Gross income is the sum of the income from all these sources before income tax and the Medicare levy have been deducted.
29 Sources from which income may be received include:
- wages and salaries (whether from an employer or own corporate enterprise)
- profit/loss from own unincorporated business (including partnerships)
- investment income (interest, rent, dividends, royalties)
- government cash transfers (pensions, allowances, benefits)
- private cash transfers (e.g. superannuation, regular workers' compensation, income from annuities and child support).
30 Receipts which are excluded from income because they are not regular or recurring cash payments include the following:
- income in kind including employee benefits such as the provision of a house or a car
- employer contributions to pension and superannuation funds
- capital transfers such as inheritances and legacies, maturity payments on life insurance policies, lump sum compensation for injuries or other damage
- capital gains and losses.
31 Receipts of family tax benefit are treated as income, regardless of whether they are received fortnightly or as a lump sum. The aged persons' savings bonus and self-funded retirees' supplementary bonus, paid as part of the introduction of 'A 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 seniors paid in 2000-01 and the one-off payments to families and carers paid in 2003-04 are included as income as they were primarily a supplement to existing government support payments.
32 While income is generally a good indicator of economic wellbeing, there are some circumstances which present particular difficulties. Some households report extremely low and even negative income in the SIH, which places them well below the safety net of income support provided by government social security (eg. Centrelink) payments. Households may under-report their incomes in the SIH at all income levels, including low income households. However, households can correctly report low levels of income if they incur losses in their unincorporated business or have negative returns from their other investments. For further information on the examination of low income households see Appendix 4, Household Wealth and Wealth Distribution, Australia, 2003-04, (cat. no. 6554.0).
33 Studies of income and expenditure reported in the 2003-04 ABS Household Expenditure Survey (HES) 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, indicating 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. The mean expenditure of households in the lowest income decile is about equal to the expenditure of households in the third income decile. It is also 15% higher than the mean expenditure of households in the second income decile, while the mean income of the lowest income decile is only 58% that of the households in the second decile. For more information on the analysis of low income households refer to appendix 4 of Household Wealth and Wealth Distribution, Australia (cat. no. 6554.0).
Weekly income
34 Income is collected using a number of different reporting periods, such as the whole financial year for own business and property income, and the usual payment for a period close to time of interview for wages and salaries, other sources of private income and government cash transfers. The income is divided by the number of weeks in the reporting period. Estimates of weekly income in this publication therefore do not refer to a given week within the reference year of the survey.
Equivalised disposable income quintiles
35 For quintile analysis in this publication, gross income (as described in the previous paragraphs) is adjusted in two ways to facilitate the comparison of economic wellbeing between households. First, disposable income is derived by deducting estimates of personal income tax and the Medicare levy from gross income. Disposable income better represents the economic resources available to meet the needs of households.
36 Equivalence scales are used to adjust the disposable incomes of households in a way that enables the analysis of the relative wellbeing of people living in households of different size and composition. This reflects the requirement of a larger household to have a higher level of income to achieve the same standard of living as a smaller household. For example, it would be expected that a household comprising two people would normally need more income than a lone person household if all the people in the two households are to enjoy the same material standard of living. Adopting a per capita analysis would address one aspect of household size difference, but would address neither compositional difference (i.e. the number of adults compared with the number of children) nor the economies derived from living together. Where disposable income is negative, equivalised disposable income is set to zero.
37 When 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.
38 The equivalence scale used in this publication was developed for the Organisation for Economic Co-operation and Development and is referred to as the 'modified OECD' equivalence scale. It is widely accepted among Australian analysts of income distribution. This scale allocates 1.0 points for the first adult (aged 15 years or older) in a household; 0.5 for each additional adult; and 0.3 for each child. Equivalised household income is derived by dividing total household income by the sum of the equivalence points allocated to household members. For example, if a household received combined gross income of $2,100 per week and comprised two adults and two children (combined household equivalence points of 2.1), the equivalised gross household income for each household member would be calculated as $1,000 per week.
39 For more information on the use of equivalence scales, readers are referred to Appendix 3 in Household Income and Income Distribution, Australia, 2003-04, (cat. no. 6523.0).
Income quintiles
40 In this publication, the income quintiles and deciles are calculated with respect to persons, including children. Such measures are sometimes known as person weighted estimates. Nevertheless, as most of the relevant characteristics of persons relate to their household circumstances, most of the tables in this publication primarily describe households.
SURVEY METHODOLOGY
Scope and coverage
41 The survey collects information by personal interview from usual residents of private dwellings in urban and rural areas of Australia, covering about 98 per cent of the people living in Australia. Private dwellings are houses, flats, home units, caravans, garages, tents and other structures that are 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.
42 The survey also excludes:
- households which contain members of non-Australian defence forces stationed in Australia
- households which contain diplomatic personnel of overseas governments
- households in collection districts defined as very remote or Indigenous Communities - this has only a minor impact on aggregate estimates except in the Northern Territory where such households account for about 23% of the population.
Data collection
43 Information for each household was collected using:
- a household level computer assisted interview questionnaire which collected information on household characteristics, assets and liabilities
- an individual level computer assisted interview questionnaire which collected information on income and other personal characteristics from each usual resident aged 15 years and over.
44 Sample copies of the above documents are available upon request and will be included in the Household Expenditure Survey and Survey of Income and Housing, Australia: User Guide, 2003-04, (cat. no. 6503.0). The user guide describes the definitions, concepts, methodology and estimation procedures used.
Sample design
45 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.
46 The SIH sample was designed in conjunction with the HES. In the combined sample, some dwellings were selected to complete both the SIH questionnaire and the HES questionnaire, while other dwellings were selected to complete the SIH questionnaire only. Dwellings were selected through a stratified, multistage cluster design. Selected clusters were split such that approximately one third of households in the cluster received only the SIH questionnaire and two thirds of households in the cluster received both the SIH and HES questionnaires. Selections were distributed randomly across a twelve month enumeration period so that the survey results are representative of income and expenditure patterns across the year. Over the year, about 80% of persons over the age of 15 in this sample responded.
Non-responding households
47 Of the 14,545 households selected in the sample, 3,184 did not respond at all to the questionnaire, or did not respond adequately. Such households included:
- households affected by death or illness of a household member
- households in which the significant person(s) in the household did not respond because they could not be contacted, had language problems or refused to participate
- households in which the significant person(s) did not respond to key questions.
Partial response and imputation
48 Some other households did not supply all the required information but supplied sufficient information to be retained in the sample. Such partial response occurs when:
- income or other data in a questionnaire are missing from one or more non-significant person's records because they are unable or unwilling to provide the data
- all key questions are answered by the significant person(s) but other data are missing
- not every person aged 15 or over residing in the household responds but the significant person(s) provide(s) answers to all key questions.
49 In the first and second cases of partial response above, the data provided are retained and the missing data are imputed by replacing each missing value with a value reported by another person (referred to as the donor).
50 For the third type of partial response, the data for the persons who did respond are retained, and data for each missing person are provided by imputing data values equivalent to those of a fully responding person (donor).
51 Donor records are selected by finding fully responding persons with matching information on various characteristics, such as state, sex, age, labour force status, income and expenditure, 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.
Final sample
52 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 14,545 in the scope of the survey, of which 11,361 (78%) were included as part of the final estimates. The final sample consists of those 11,361 households, comprising 22,315 persons aged 15 years old and over. The final sample includes 2,812 households which had at least one imputed value in either income or assets and liabilities. Nearly 70% of these households had only a single value missing, and most of these were for superannuation assets or a minor source of income for the household.
SIH FINAL SAMPLE: NUMBER OF HOUSEHOLDS, 2003-04 |
| |
| CAPITAL CITY | BALANCE OF STATE | TOTAL | |
| Households | Persons(a) | Households | Persons(a) | Households | Persons(a) | |
| no. | no. | no. | no. | no. | no. | |
| |
NSW | 1 537 | 3 131 | 1 093 | 2 117 | 2 630 | 5 248 | |
Vic. | 1 690 | 3 474 | 696 | 1 338 | 2 386 | 4 812 | |
Qld | 845 | 1 607 | 1 151 | 2 236 | 1 996 | 3 843 | |
SA | 890 | 1 713 | 367 | 701 | 1 257 | 2 414 | |
WA | 950 | 1 909 | 490 | 929 | 1 440 | 2 838 | |
Tas. | 423 | 811 | 400 | 739 | 823 | 1 550 | |
NT | 335 | 666 | 87 | 161 | 422 | 827 | |
ACT | 407 | 783 | - | - | 407 | 783 | |
Aust. | 7 077 | 14 094 | 4 284 | 8 221 | 11 361 | 22 315 | |
| |
- nil or rounded to zero (including null cells) |
(a) Number of persons aged 15 years and over. |
Weighting
53 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).
54 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.
55 The SIH survey was benchmarked to the in scope estimated resident population (ERP) and the estimated number of households in the population.
56 Three types of benchmarks are used in the calibration of the final weights:
- numbers of persons aged 15 and over
- numbers of children under age 15
- numbers of households.
57 Person benchmarks for persons aged 15 and over are estimates of the number of people in each state and territory by age and sex, the number of people in each state and the ACT by labour force status, and the number of people in each state living in the capital city or the balance of the state.
58 A separate set of benchmarks is used for children under 15, since there are not individual person records for them in the survey. Information about children is recorded on household records, however, and benchmarks for the number of children aged 0-4 and aged 5-14 are used for each state and territory.
59 Numbers of households are calibrated to benchmarks for total Australia with respect to household composition (based on the number of adults (1, 2 or 3) and whether or not the household contains children).
60 The person and household benchmarks are based on estimates of numbers of persons and households in Australia. The benchmarks are adjusted to include persons and households residing in private dwellings only and therefore do not, and are not intended to, match estimates of the Australian resident population published in other ABS publications.
Estimation
61 Estimates produced from the survey are usually in the form of averages (e.g. mean weekly housing costs of couples with dependent children), or counts (e.g. total number of households which own their dwelling or total number of persons living in households that own their own dwelling). For counts of households, the estimate is obtained by summing the weights of all households in the required group (e.g. those owning their own dwelling). For counts of persons, the household weights are 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 other detailed data are only collected for people 15 years and older. Therefore, counts of persons cannot be obtained by summing the weights of all persons.
Reliability of estimates
62 The estimates provided in this publication are subject to two types of error, non-sampling and sampling error.
Non-sampling error
63 Non-sampling error can occur whether the estimates are derived from a sample or from a complete collection. Major sources of non-sampling error include the following:
- Non-sample error can arise through the inability to obtain data from all households included in the sample. Although adjustments are made through the weighting process to reflect the differing response rates of various groups in the population, some non-response bias may remain because of differences that exist between the characteristics of respondents and non-respondents
- There can also be errors in reporting on the part of both respondents and interviewers. Reporting errors may arise through inappropriate wording of questions, misunderstanding of what data are required, inability or unwillingness to provide accurate information, or mistakes in answers to questions
- Errors may also arise during processing of the survey data through mistakes in coding and data recording.
64 Non-sampling errors are difficult to measure in any collection. However, every effort is made to minimise these errors. In particular, the effect of the reporting and processing errors described above is minimised by careful questionnaire design, intensive training and supervision of interviewers, asking respondents to refer to records whenever possible and by extensive editing and quality control checking at all stages of data processing.
65 The error due to incomplete response is minimised by:
- call-backs to all initially non-responding households in order to explain the importance of their cooperation to the survey
- adjustment to the weights allocated to the respondent households in order to allow for households with similar characteristics from which comprehensive data are not obtained.
Sampling error
66 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 Appendix 2.
SPECIAL DATA SERVICES
67 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 analytic 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. For further information, contact ABS information consultants on 1300 135 070.
UNIT RECORD FILE
68 A confidentialised unit record file (CURF) from the 2003-04 SIH will be released on CD-ROM in 2006. It is also expected that a more detailed SIH CURF will be available through the ABS Remote Access Data Laboratory. A full range of up-to-date information about the availability of ABS CURFs and about applying for access to CURFs is available via the ABS web site <https://www.abs.gov.au> (see Services We Provide, Confidentialised Unit Record Files (CURFs)). Inquiries to the ABS CURF Management Unit should email: curf.management@abs.gov.au, or telephone (02) 6252 5853.
ACKNOWLEDGMENT
69 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.
RELATED PUBLICATIONS
70 Users may wish to refer to the following ABS products which relate to housing costs:
- Australian Housing Survey, Housing Characteristics, Costs and Conditions, 1999, (cat. no. 4182.0)
- Government Benefits, Taxes and Household Income, Australia, 1998-99, (cat. no. 6537.0)
- Household Expenditure Survey and Survey of Income and Housing, Australia: User Guide, 2003-04, (cat. no. 6503.0)
- Household Expenditure Survey, Australia: Summary of Results, 2003-04, (cat. no. 6530.0)
- Household Expenditure Survey, Australia: Detailed Expenditure Items, 2003-04, (cat. no. 6535.0)
- Household Income and Income Distribution, Australia, 2003-04, (cat. no. 6523.0)
- Household Income and Income Distribution, Australia - Detailed tables, 2003-04, (cat. no. 6523.0.55.001)
- Housing Occupancy and Costs, Australia, 1997-98, (cat. no. 4130.0)
- Housing Occupancy and Costs, Australia, 2000-01, (cat. no. 4130.0.55.001)
- Housing Occupancy and Costs, Australia, 2002-03, (cat. no. 4130.0.55.001)
- Survey of Income and Housing Costs and Amenities: Income Units, Australia, 1990, (cat. no. 6523.0)
- Survey of Income and Housing Costs, Australia: User Guide, 1997, (cat. no. 6553.0)
- Measuring Wellbeing: Frameworks for Australian Social Statistics, 2001, (cat. no. 4160.0)
- Measuring Australia's Progress, 2004, (cat. no. 1370.0)