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EXPLANATORY NOTES
Introduction
1 This publication presents results from the 2015 Survey of Disability, Ageing and Carers (SDAC), conducted throughout Australia by the Australian Bureau of Statistics (ABS). This is the eighth comprehensive national survey undertaken by the ABS to measure disability, following similar surveys in 1981, 1988, 1993, 1998, 2003, 2009 and 2012. Some key data from the 2015 SDAC was released in April 2016 in the publication Disability, Ageing and Carers, Australia, First Results, 2015. For completeness, all tables from that publication have been reproduced in this release.
2 The aims of the survey are to:
- measure the prevalence of disability in Australia
- measure the need for support of older people and those with disability
- provide a demographic and socio-economic profile of people with disability, older people and carers compared with the general population
- estimate the number of and provide information about people who provide care to people with disability, long-term health conditions and older people.
3 The main concepts for this publication are defined separately within the Glossary.These are:
- disability
- long-term health condition
- specific limitation or restriction
- core activity limitation and levels of restriction
- need for assistance.
4 The survey collected detailed information from three target populations:
- people with disability
- older people (i.e. those aged 65 years and over)
- people who care for those with disability; who have a long-term health condition; or who are aged 65 years and over
Scope and coverage of the survey
5 The scope of the 2015 SDAC was people in both urban and rural areas in all states and territories, living in private dwellings, self-care retirement villages and establishments providing long-term cared accommodation. The survey excluded the following:
- certain diplomatic personnel of overseas governments, customarily excluded from the Census and estimated resident population
- people whose usual place of residence was outside Australia
- members of non-Australian defence forces (and their dependents) stationed in Australia
- people living in hotels, motels and short term caravan parks
- people living in religious and educational institutions
- people living in hostels for the homeless or night shelters
- people living in gaols or correctional institutions
- people living in staff quarters, guest houses, boarding houses or other long-term accommodation
- people living in very remote areas
- discrete Aboriginal and Torres Strait Islander communities.
6 The scope of the 2015 SDAC was narrower than previous surveys which also enumerated:
- people living in hotels, motels and short term caravan parks
- people living in religious and educational institutions
- people living in hostels for the homeless or night shelters
- people living in staff quarters, guest houses, boarding houses or other long-term accommodation.
The reduction in scope, which represents less than 1% of total Australian population, was found to have little to no impact on the accuracy and data quality for key data items.
7 Both the 2012 and 2015 surveys excluded discrete Aboriginal and Torres Strait Islander communities from their estimates. These communities are found in Queensland, South Australia, Western Australia and the Northern Territory. This exclusion has minimal impact on Australia level estimates. However, it could have an impact on Northern Territory estimates, as around 10% of Northern Territory households that were included before 2012 are now excluded. Most of the discrete Aboriginal and Torres Strait Islander communities are located in very remote areas of Australia. |
8 The survey also collected a small amount of information about people not in the target populations, allowing for comparison of demographic and socio-economic characteristics of the target populations with the general population.
9 The coverage of the SDAC was the same as the scope. Rules were applied to maximise the likelihood that each person in coverage was associated with only one dwelling and thus had one chance of selection.
10 Usual residents of private dwellings and self-care retirement villages were included in the survey unless they were away on the night of enumeration and were likely to be away for the remainder of the enumeration period.
11 Visitors to private dwellings and self-care retirement villages were excluded from coverage as the expectation was that most would have their chance of selection at their usual residence.
12 Occupants of long-term cared-accommodation establishments in scope of the survey were enumerated if they had been, or were expected to be, a usual resident of an establishment for three months or more. |
Sample design
13 Multi-stage sampling techniques were used to select the sample for the survey. Private dwellings and self-care retirement village units, collectively referred to as the household component, included approximately 25,500 fully responding private dwellings (from the ABS private dwellings frame) and 250 fully responding self-care retirement village units (from the ABS special dwellings frame). For the cared-accommodation sample approximately 1,000 health establishments fully responded to the survey.
| Table 1.1 Household component (private dwellings), response rates | Number | % |
| Fully responding | 25 555 | 80.0 |
 | | | |
| Non response | | |
| Refusal | 1 172 | 3.7 |
| Non response | 4 987 | 15.6 |
| Part response | 243 | 0.8 |
| Total | | 6 402 | 20.0 |
| | | |
| Total | | 31 957 | 100.0 |
| | |
| Table 1.2 Household component (self-care retirement villages), response rates | Number | % |
| Table 1.3 Cared-accommodation component, response rates | Number | % |
| Responding establishments | 1 009 | 89.4 |
| Non-responding establishments | 120 | 10.6 |
| | |
| Total | 1 129 | 100.0 |
14 After exclusions due to scope and coverage, the final combined sample was 75,211 people, comprising 63,515 people from the household component and 11,696 people from the cared-accommodation component.
Household component
15 Private dwellings were selected at random using a multi-stage area sample of private dwellings to ensure that all sections of the population living within the geographic scope of the survey were represented. To improve the sample take of people in the target population, a larger allocation of households was selected from socio-economic areas which were known to have a higher representation of people with disability.
16 Self-care retirement villages were selected separately from the private dwellings based on a list of all non-private dwellings in Australia. In 2015, while the list included hotels, motels, boarding houses and short term caravan parks, only self-care retirement villages were chosen for the household component as the inclusion of the other types of accommodation would have minimal impact on estimates.
17 Similar to the private dwelling selection process, the list of self-care retirement villages was first modified to meet the scope and coverage requirements of the survey, which excluded dwellings in very remote areas, collection districts containing a discrete Aboriginal or Torres Strait Islander community, boarding schools, correctional institutions and other accommodation types noted in paragraph 5 above.
Cared-accommodation component
18 The cared-accommodation establishment sample was chosen separately from other samples. A frame was constructed which included all Australian businesses which may provide adequate facilities to support long-term cared-accommodation.
19 A census was then conducted of those establishments on the frame to ensure they provided long-term cared-accommodation. This process is explained further in the Data Collection section of these Explanatory Notes.
20 Each in-scope establishment was given a chance of selection proportional to the average number of persons it accommodated. If a health establishment was selected, the nominated contact officer was required to select a sample of occupants in their establishment. The contact officer then used a random selection technique to identify the occupants to be included in the survey. |
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Data collection
21 Similar to the 2003, 2009 and 2012 surveys, the 2015 enumeration collected information about people living in households as well as those in cared-accommodation to ensure the survey represented a comprehensive picture of disability in Australia. This was achieved by conducting the survey in two separate parts: the household component and the cared-accommodation component, using different methods for data collection and processing.
22 In 2015, the household component covered people in private dwellings such as houses, flats, home units, townhouses and self-care components of retirement villages.
23 In this publication, people in the household component of the survey are referred to as 'living in households'.
24 The cared-accommodation component covered residents of hospitals, nursing homes, hostels and other homes, who had been, or were expected to be, living there or in another health establishment for a period of three months or more. |
Household component
25 Data for the household component of the survey were collected by trained interviewers, who conducted computer-assisted personal interviews. The interviews were conducted from 5 July to 19 December 2015.
26 Households containing people with disability or those aged 65 years and over, were determined through a series of screening questions asked of a responsible adult in the selected household.
27 Households containing people who were carers of persons with a core activity limitation, living either in the same household or elsewhere, or who provided any care to persons living elsewhere, were identified using two methods:
- through a series of screening questions asked of a responsible adult in the household and, when applicable,
- through information provided by recipients of care during their personal interview.
28 Where possible, a personal interview was conducted with people identified in the above populations. Proxy interviews were conducted for:
- children aged less than 15 years
- those aged 15 to 17 years whose parent or guardian did not consent to them being personally interviewed
- those incapable of answering for themselves due to illness, impairment, injury or language problems.
29 People with disability were asked questions relating to:
- help and assistance needed and received for mobility, self-care, communication, cognitive or emotional tasks, health care, household chores, property maintenance, meal preparation, reading and writing tasks and transport activities
- use of aids and equipment
- schooling restrictions, for those aged 5 to 20 years
- employment restrictions
- satisfaction with the quality of services received and range of services available
- accessibility and discrimination related to disability
- National Disability Insurance Scheme (NDIS) participation
- internet use
- self-perception of health and well-being
- access and barriers to health care
- social and community participation
- feelings of safety.
30 People aged 65 years and over without disability were asked questions relating to:
- self-perception of health and well-being
- help and assistance needed and received for household chores, property maintenance, meal preparation, reading and writing tasks, and transport activities
- satisfaction with the quality of services received and range of services available
- internet use
- social, and community participation
- feelings of safety
31 People who confirmed they were the primary carer of a person with disability were asked questions relating to:
- the type of care they provide
- the support available to them
- internet use
- self-perception of health and well-being
- access and barriers to health care
- social and community participation
- the effect that the caring role has on their lives, relating to their own health, well-being and workforce participation
- their attitudes to, and experience of, their caring role
Some of this information was collected through a self-enumeration form.
32 Basic demographic and socio-economic information was collected for all people in the household. This information was generally provided by a responsible adult in the household, or if preferred, by personal interview of each respondent.
Cared-accommodation component
33 The cared-accommodation component was enumerated in two stages using both web and mail-based methodologies directed to administrators of selected health establishments.
34 The first stage involved a census of all known health establishments in Australia. These establishments were sent an approach letter from the ABS, detailing their selection and the requirement for a suitable employee of their establishment to complete a web-based Contact Information Form. This form collected the name and role of a contact officer for the establishment, whether the establishment offered cared-accommodation to occupants on a long-term basis (i.e. for a period of three months or more), the current number of occupants within the cared-accommodation component, and the type of establishment.
35 The second stage, conducted from 25 May to 31 July 2015, was based on a sample of the health establishments that indicated their ability to provide long-term cared-accommodation in stage one. Each establishment was given a likelihood of selection relative to the number of long-term occupants they had reported. If a health establishment was selected, the nominated contact officer was required to select a sample of occupants in their establishment, following the instructions provided. The contact officer then completed a separate questionnaire for each selected occupant.
36 The range of data collected in the cared-accommodation component was narrower than in the household component as some topics were not suitable for collection through a proxy or were irrelevant to those residing in cared-accommodation. |
Processing procedures
Collection
37 A number of editing techniques were implemented within the computer-assisted survey instrument to assist with processing data collected by the personal interviews, such as:
- the programming of 'edits' relating to the range and consistency of answers, which would prompt interviewers to check the correctness of responses and would not allow implausible results to be accepted
- the inclusion of pick lists and coders, resulting in a high proportion of coding being automated at the time of data collection.
Coding of Long-term health conditions
38 The majority of reported long-term health conditions were automatically coded to a list of approximately 1,000 health conditions, within the computer-assisted personal interview. Those conditions that could not be automatically coded at the time of data collection were reviewed on a case by case basis by ABS employees during post-collection editing.
39 The code list used for the 2015 SDAC was similar to that used in previous surveys, with some minor updates. Conditions classified at the full level of detail are not generally available for output from the survey, however, they can be regrouped in various ways for output. The output classification, developed for the SDAC, is based on the International Classification of Diseases: 10th Revision (ICD-10). For a concordance of codes used in the 2015 SDAC with the ICD-10 please refer to the Long-term Health Conditions ICD-10 Concordance spreadsheet available in the Downloads tab. |
Editing
40 An extensive range of edits and quality checks were performed on the aggregated data file, after the completion of data collection. These included:
- ensuring there were no contradictory responses and that relationships between items were within acceptable limits
- identifying cases which, although not necessarily errors, were sufficiently unusual or close to specified limits as to warrant examination
- a review of incomplete data and responses that could not be automatically coded at the time of collection, to determine if these responses could be coded or categorised appropriately.
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Weighting, benchmarking and estimation
41 Weighting is a process of adjusting results from a sample survey to infer results for the in-scope total population. To do this, a weight is allocated to each sample unit; for example, a household or a person. The weight is a value which indicates how many population units are represented by the sample unit.
42 The first step in calculating weights for each person was to assign an initial weight, which was equal to the inverse of the probability of being selected in the survey. For example, if the probability of a person being selected in the survey was 1 in 300, then the person would have an initial weight of 300 (that is, they represent 300 others). An adjustment was then made to these initial weights to account for the time period in which a person was assigned to be enumerated.
43 The cared-accommodation component of the survey was weighted separately from the household component. These two components together represent the entire in-scope population.
44 The weights of the household component were calibrated to align with independent estimates of the population of interest, referred to as 'benchmarks', in designated categories of sex by age by area of usual residence. The weights of the cared-accommodation component were calibrated to benchmarks in categories by state. Weights calibrated against population benchmarks ensure that the survey estimates conform to the distribution of the population rather than to the distribution within the sample itself. Calibration to population benchmarks helps to compensate for over or under-enumeration of particular categories of persons which may occur due to either the random nature of sampling or non-response.
45 The household component of the survey was benchmarked to the estimated resident population (ERP) in each state and territory living in households, excluding those in very remote areas of Australia and in collection districts in non-very remote areas containing one or more discrete Aboriginal or Torres Strait Islander communities, as at 30th September 2015. The cared-accommodation component of the survey was benchmarked to population counts derived from the census of this component, incorporating a non-response adjustment. The SDAC estimates do not (and are not intended to) match estimates for the total Australian population obtained from other sources (which may include people living in non-private dwellings, very remote parts of Australia and people living in discrete Aboriginal or Torres Strait Islander communities).
46 Survey estimates of counts of people are obtained by summing the weights of persons with the characteristic of interest. Estimates of non-person counts (for example, number of health conditions) are obtained by multiplying the characteristic of interest with the weight of the reporting person and aggregating.
47 Age standardisation is a way of allowing comparisons between two or more populations with different age structures, in order to remove age as a factor when examining relationships between variables. For example, the age structure of the population of Australia is changing over time. As the prevalence of a particular disability may be related to age, any increase in the proportion of people with that health condition over time may be due to real increases in prevalence or to changes in the age structure of the population over time or to both. Age standardising removes the effect of age in assessing change over time or between different populations.
48 For this publication the direct age standardisation method was used. The standard population used was the 30 June 2001 Estimated Resident Population. The age categories used in the standardisation for this publication were five year age groups, to 75 years and over. There are 3 tables in this publication that present age standardisation. Totals presented in Tables 1 and 2 comparing rates over time are shown as age-standardised percentages. There is also an age standardised disability rate presented in table 4 for states and territories, remoteness, country of birth and main language spoken at home.
Reliability of estimates
49 All sample surveys are subject to sampling and non-sampling error.
50 Sampling error is the difference between estimates, derived from a sample of persons, and the value that would have been produced if all persons in scope of the survey had been included. Indications of the level of sampling error are given by the Relative Standard Error (RSE) and 95% Margin of Error (MOE). For more information refer to the Technical Note - Data quality.
51 In this publication, estimates with an RSE of 25% to 50% are flagged to indicate that the estimate has a high level of sampling error relative to the size of the estimate, and should be used with caution. Estimates with an RSE over 50% are also flagged and are generally considered too unreliable for most purposes.
52 Margins of Error are provided for proportions to assist users in assessing the reliability of these data. The proportion combined with the MOE defines a range which is expected to include the true population value with a given level of confidence. This is known as the confidence interval. This range should be considered by users to inform decisions based on the proportion.
53 Non-sampling error may occur in any data collection, whether it is based on a sample or a full count such as a census. Non-sampling errors occur when survey processes work less effectively than intended. Sources of non-sampling error include non-response, errors in reporting by respondents or in recording of answers by interviewers, and errors in coding and processing data.
54 Non-response occurs when people are unable to or do not respond, or cannot be contacted. Non-response can affect the reliability of results and can introduce a bias. The magnitude of any bias depends on the rate 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.
55 The following methods were adopted to reduce the level and impact of non-response:
- face-to-face interviews with respondents
- the use of proxy interviews in cases where language difficulties were encountered, noting the interpreter was typically a family member
- follow-up of respondents if there was initially no response
- weighting to population benchmarks to reduce non-response bias.
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The Output File
56 To produce tabular estimates and other outputs from the collected data, information from the survey was stored on an output file in the form of data items. In some cases items were formed directly from information recorded in individual survey questions, in others, data items were derived from answers to several questions (e.g. the item 'disability status' is derived from the responses to approximately 80 questions).
57 In designing the output data file, the aim was to create a file that was similar to the one from the 2012 survey. The result is a ten level hierarchical output file, the structure of which is as follows:
- household level, containing information about the household size and structure and household income details
- family level, containing information about the family size and structure, including whether there is a carer and/or a person with disability in the family
- income unit level, containing information about the income unit size and whether there is a primary carer in the income unit
- person level, which is the main level, containing all demographic and socio-economic characteristics of the survey respondents, and most of the health and related information they provided
- all conditions level, containing detailed information about the long-term health conditions reported in the survey
- restrictions level, containing detailed information about the restrictions reported in the survey
- specific activities level, containing detailed information about how much support people need to perform specific activities, such as moving about their place of residence
- recipient level, containing detailed information on respondents who need help or supervision with everyday activities because of their age or disability, including types of assistance they need
- broad activities level, containing detailed information about how much support people need to perform tasks at the broad activity level (e.g. mobility, communication)
- assistance providers level, containing detailed information on people providing assistance to others because of age or disability, including the types of assistance they provide.
58 The first four levels are in a hierarchical relationship: a person is a member of an income unit, which is a member of a family, which is a member of a household. Levels five to nine are in a hierarchical relationship with the person level and level ten is in a hierarchical relationship with level nine. All person and lower level records link to a household, family and income unit record. However, lower level records only exist where the person is in the relevant population.
59 Data about households and families are contained as individual characteristics on person records. A full list of output data items available from the survey can be accessed from the Downloads tab.
Interpretation of results
Measuring disability
60 Disability is a difficult concept to measure because it depends on a respondent's perception of their ability to perform a range of activities associated with daily living. Factors discussed below should also be considered when interpreting the estimates contained in this publication.
61 Information in the survey was based, wherever possible, on the personal response given by the respondent. However, in cases where information was provided by another person, some answers may differ from those the selected person would have provided. In particular, interpretation of the concepts of 'need' and 'difficulty' may be affected by the proxy-interview method.
62 A number of people may not have reported certain conditions because of:
- the sensitive nature of the condition (e.g. alcohol and drug-related conditions, schizophrenia, other mental health conditions)
- the episodic or seasonal nature of the condition (e.g. asthma, epilepsy)
- a lack of awareness of the presence of the condition on the part of the person reporting (e.g. mild diabetes) or a lack of knowledge or understanding of the correct medical terminology for the condition
- the lack of comprehensive medical information kept by their cared-accommodation establishment.
63 As certain conditions may not have been reported, data collected from the survey may have underestimated the number of people with one or more disabilities.
64 The need for help may have been underestimated as some people may not have admitted needing help because of such things as a desire to remain independent, or may not have realised help was needed with a task because help had always been received with that task.
65 The criteria by which people assessed whether they had difficulty performing tasks may have varied. Comparisons may have been made with the ability of others of a similar age, or with the respondent's own ability when younger.
66 The criteria used to identify disability and disability status has changed between 2012 and 2015. New modules were added to identify people with social and behavioural difficulties, memory loss and periods of confusion and dementia.
67 The different collection methods used (personal interview for households, and administrator completed forms for cared-accommodation) may have had some effect on the reporting of need for assistance with core activities. As a result there may have been some impact on measures such as disability status. If so, this would have more impact on the older age groups because of their increased likelihood of being in cared-accommodation. |
Primary carer completion of the self-enumeration form
68 In this survey, people who confirmed they were the primary carer of a person with disability were also asked to complete a self-enumeration form which asked questions relating to their attitudes to, and experience of, their caring role. Self-enumeration is seen as the most appropriate method of achieving response to these topics, due to the personal nature of the questions.
69 Some data items in the publication, which relate to primary carers, are derived from questions answered in the self-enumeration form. In 2015, these forms had levels of non-response (described as the 'not stated' population) which were higher than the levels reported for the interviewer administered questions. Non response to specific questions varied ( from 13.6% to 15.6%).
70 Non-response introduces the potential for bias if those who did respond to the self completion questionnaire were inherently different to the total population of primary carers. Analysis of 2015 data showed that, with one exception, there were no statistically significant differences between the characteristics of all primary carers and those who responded to the self completion questionnaire. The one exception was country of birth where respondents to the self completion questionnaire born in main non-English speaking countries were fewer than would be expected given their prevalence in the general population. While 18% of primary carers were from non-English speaking backgrounds, they represented only 16% of those who responded to the self-completion questionnaire. |
71 In this publication, proportions have been calculated excluding 'not stated' responses (excluded from both the numerator and the denominator for items derived from the primary carers' self enumeration form). Users should take this into consideration when reviewing output derived from the self-enumeration form.
Comparability with previous Surveys of Disability, Ageing and Carers
72 Much of the content of the eight disability surveys conducted by the ABS is comparable. There are differences, however, as later surveys have attempted to obtain better coverage of disability and of specific tasks and activities previously considered too sensitive for a population survey. A list of output data items from the 2015 survey can be accessed from the Downloads tab of this release.
73 Listed below are some of the changes made to the 2015 survey:
Items that have been updated include:
- Self-Perception of Health and Well-being: The population asked this module has been extended to include people aged 65 years and over without disability.
- Patient experience: People aged 65 years and over without disability are no longer asked this module.
- Employment restrictions: People with disability aged 65 years and over living in households are now asked this module.
- Whether has a disability: The definition has changed with three new modules added to the disability identification module comprising: social and behavioural difficulties; memory loss and periods of confusion; and dementia. A data item which uses the 2012 definition is still available. This definitional change does not have a statistically significant impact on the proportion of people classified as having disability.
- Labour Force: A number of minor changes have been made to labour force data items to align with standard outputs from the Labour Force Survey (cat. no. 6202.0).
- Non-private dwellings: Selected non-private dwellings have been removed from the scope of the Survey. They include: hotels, motels, boarding houses and short term caravan parks which were removed from the sample due to the difficulty in enumeration for the relatively small number of fully responding participants.
- Self-care retirement villages: Self-care retirement village units, previously considered non-private dwellings, were reclassified in 2015 to private dwellings for weighting purposes to align with the Census classifications. Self-care retirement village units combined with private dwellings are collectively called households.
- Experience of Homelessness: This module has been removed in the 2015 survey.
- Self perception of health and well-being (SF12): The Short Form 12 questions used in 2012 were replaced with the Kessler Psychological Distress Scale (K10) questions.
- Assistance Needed and Received: Data items have had a number of minor changes to more accurately reflect the applicable populations.
- Aids used: Response categories have been added / updated to better reflect current aids available for use. For example, mobile apps have been added to both mobility and communication aids.
- Internet Use: Questions have been updated to reflect changes in methods of access and purpose for access. In line with other ABS collections the reference period was also changed from 12 months to 3 months. Primary carers are now also asked these questions. Other questions in the survey were also updated to reflect changes in technology including the addition of assistive communication apps on mobile devices and types of non-spoken communication used because of disability.
- Social and Community participation: Some questions have been removed and others updated.
New items for SDAC 2015 include:
- Social and behavioural difficulties; Memory loss and periods of confusion; and Dementia: Three modules have been added to better identify disability. The addition of these modules may affect the comparability of data for these conditions with earlier cycles of the survey as some respondents may not have considered these to be health conditions appropriate for inclusion in the survey.
- Discrimination and Accessibility: Two modules have been added in response to a growing interest by a number of government departments. The new data relate to difficulty accessing locations, venues and facilities due to disability; discrimination experienced and situations avoided due to disability; and sources of unfair treatment or discrimination due to disability.
- National Disability Insurance Scheme (NDIS) participation: A question has been added to measure the number of people who are participating in the NDIS as a baseline for future surveys as the rollout of NDIS continues.
- Provision of care: Questions have been added to better understand the impact of being a carer on a person's employment. This includes accessibility to leave and other special working arrangements.
- Number of bedrooms: A question has been added for those living in private dwellings to calculate a proxy occupancy standard based on a Canadian model.
- Types of medical aids used: New questions have been asked to determine the use of selected medical aids.
- Primary Health Network area (PHNs): This geography has been added in 2015.
- Disability in school: Two questions have been added to determine whether special support or more assistance is needed at school or an educational institution.
For further information on the comparability of data items and new data items see the 2015 SDAC Data Item List, which can be accessed from the Downloads tab.
Classifications
Socio-economic indexes for Areas (SEIFA)
81 Socio-economic Indexes for Areas (SEIFA) is a suite of four summary measures that have been created from 2011 Census information. Each index summarises a different aspect of the socio-economic conditions of people living in an area. The indexes provide more general measures of socio-economic status than is given by measures such as income or unemployment alone.
82 SEIFA uses a broad definition of relative socio-economic disadvantage in terms of people's access to material and social resources and their ability to participate in society. While SEIFA represents an average of all people living in an area, it does not represent the individual situation of each person. Larger areas are more likely to have greater diversity of people and households.
83 For more detail, see the Census of Population and Housing: Socio-Economic Indexes for Areas (SEIFA), Australia, 2011 (cat. no. 2033.0.55.001).
Rounding
84 Estimates presented in this publication have been rounded.
85 Proportions presented in this publication are based on unrounded estimates. Calculations using rounded estimates may differ from those published. |
Confidentiality
86 The Census and Statistics Act,1905 provides the authority for the ABS to collect statistical information, and requires that statistical output shall not be published or disseminated in a manner that is likely to enable the identification of a particular person or organisation. This requirement means that the ABS must take care and make assurances that any statistical information about individual respondents cannot be derived from published data.
87 Care is taken in the specification of tables to minimise the risk of identifying individuals. In addition, a technique has been developed to randomly adjust cell values. Random adjustment of the data is considered to be the most satisfactory technique for avoiding the release of identifiable data. When the technique is applied, all cells are slightly adjusted to prevent any identifiable data being exposed. These adjustments result in small introduced random errors. These introduced random errors will in general result in tables not being 'Internally consistent' (i.e. interior cells not adding up to the totals). However, the information value of the table as a whole is not impaired. The technique allows very large/detailed tables, for which there is a strong client demand, to be produced even though they contain cells of very small numbers.
88 Similar to 2012, perturbation has been applied to 2015 data. SDAC data from surveys before 2012 presented in this publication have not been perturbed, but have been confidentialised if required using suppression of cells. |
Acknowledgements
| 89 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. |
Products and services
90 Results from the 2015 SDAC have previously been released in a publication of first results containing a subset of key data. These tables have been repeated in this main release publication.
91 Further data will be released in a range of formats including:
- this main release publication which includes a Summary of Findings and data cubes (spreadsheet format) containing a broad selection of national estimates
- a set of data cubes containing a broad selection of estimates for each state and territory (subject to standard error and confidentiality constraints and excluding time series tables) by early 2017
- a Confidentialised Unit Record File (CURF) - subject to the approval of the Australian Statistician.The basic CURF will be available via CD ROM by early 2017.
- a TableBuilder product. The TableBuilder will be accessible via the ABS website using a secure log-on portal in October 2016.
- a number of supplementary themed publications, release progressively following the release of this main release publication.
- tables produced on request to meet specific information requirements from the survey. Tables are subject to confidentiality and sampling variability constraints.
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Related publications
92 Other ABS publications which may be of interest are shown under the 'Related Information' tab of this release.
93 Current publications and other products released by the ABS are listed on the ABS website. The ABS also issues a daily Release Advice on the website which details products to be released in the week ahead. |
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