Sampling

The Survey of Income and Housing (SIH) collects information by personal interview from usual residents of private dwellings in urban and rural areas of Australia (excluding Very Remote areas), covering about 97% of the people living in Australia. Private dwellings are houses, flats, home units, caravans, garages, tents and other structures that were used as places of residence at the time of interview. Long-stay caravan parks are also included. These are distinct from non-private dwellings which include hotels, boarding schools, boarding houses and institutions. Residents of non-private dwellings are excluded.

Usual residents excludes:

• households that contain members of non-Australian defence forces stationed in Australia
• households that contain diplomatic personnel of overseas governments
• households in areas defined as Very Remote - this has only a minor impact on aggregate estimates, except in the Northern Territory where such households account for about 23% of the population.

For most states and territories, the exclusion of people in Very Remote areas has only a minor impact on any aggregate estimates that are produced because they constitute just a small proportion of the population. Very Remote and Remote areas are defined by the assignment of an Accessibility/Remoteness Index of Australia (ARIA) score. ARIA is a remoteness value (a continuous variable between 0 and 15) that measures the physical distance which separates people in a particular area and where their goods, services and opportunities for social interaction may be accessed.

The ARIA categories, and how ARIA scores are calculated, are further explained in the Australian Statistical Geography Standard (ASGS).

The 2019–20 SIH was carried out from July 2019 to June 2020. During this time, Australians were impacted by bushfires and COVID-19. The data collection design for this survey was optimised to meet operational objectives. As a result, the sample design and collection of 2019-20 SIH does not accurately reflect the household impacts of the bushfires nor COVID-19.

Information was collected only from usual residents. Usual residents were residents who regarded the dwelling as their own or main home. Other people present were considered to be visitors and were not asked to participate in the survey.

The SIH sample was designed to produce reliable estimates for broad aggregates of income, wealth, housing data for household residents in private dwellings of Australia, the State and Territories and for the capital cities and rest of state. More detailed estimates should be used with caution, especially for Tasmania, the Northern Territory and the Australian Capital Territory due to smaller samples in these localities. For more information see the 'Reliability of Estimates' section of this publication.

In 2019–20 dwellings were selected through a stratified, multistage cluster design from the private dwelling framework of the ABS Population Survey Master Sample. Selections were distributed across a twelve month enumeration period so that the survey results are representative of income patterns across the year.

The collection methodology for 2019–20 included the introduction of an online form (formally; computer assisted web interview, or CAWI), where the respondent could self report (without interviewer assistance). As a result, estimates may not be directly comparable to previous cycles. Please see the methodology page for more information.

In the 2019–20 SIH, 23,552 dwellings were initially selected for the main sample. When fieldwork commenced some dwellings selected for inclusion in the main sample were found to be out of scope units. Collectively these are referred to as sample loss, and are composed of the following groups:

• dwellings that are out of scope of the survey, under construction, demolished, or converted to non-private dwellings or non-dwellings
• vacant private dwellings
• private dwellings that contain only visitors or out of scope residents (e.g. dwellings occupied by foreign diplomats and their dependants).

In 2019–20, the SIH sample loss was 3,458 dwellings which accounted for 17% of the selected sample.

Sometimes dwellings that have been selected for inclusion in a survey are found to comprise more than one actual dwelling because an additional residence, such as a 'granny flat', has been added to the original dwelling. In such cases, each actual dwelling becomes a separate household. For privacy reasons, residents of a selected dwelling can request that their details be provided separately from other dwelling residents. A separate household is then created for each group of residents. A separate household is then created for each group of residents. In 2019–20 SIH, 11 shared dwellings were split into separate households.

A further 4,580 dwellings (19%) did not respond at all to the questionnaire or did not respond adequately. Most of these were not able to take part in the survey during the collection period or were contacted but either refused to respond or were not able to respond adequately. Other reasons included: 

• households affected by death or illness of a household member
• households which did not respond due to communication barriers or because they refused to participate.

This also included 68 households were excluded because the main income earners in the household did not adequately respond to questions about income sources and amounts. 
 

Of the selected dwellings (19,263) that were contacted and in scope of the survey, 15,011 (78%) households were included as part of the final estimates.