SAMPLING


SCOPE AND COVERAGE

Scope

The Survey of Income and Housing (SIH) collect 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; and
• households in Statistical Areas Level 1 (SA1) defined as Very Remote - this has only minor impact on aggregate estimates except in the Northern Territory where 23% of people live in Very Remote areas.

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): Volume 5 - Remoteness Structure, July 2011 (cat. no. 1270.0.55.005).

Coverage

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.


SAMPLE DESIGN AND SELECTION

Sample design

The SIH sample was designed to produce reliable broad aggregate estimates of total income for household residents in private dwellings for Australia, the State and Territories and for the Capital Cities. 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 2013–14, 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.

Selected dwellings, sample loss and selected households

In 2013–14, 21,721 dwellings were initially selected for the SIH sample. When fieldwork commenced some dwellings selected for inclusion in the SIH 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; and
• private dwellings that contain only visitors or out of scope residents (e.g. dwellings occupied by foreign diplomats and their dependants).

In 2013–14, sample loss accounted for 16% 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. In 2013–14, 39 selected dwellings were split into two households and seven were split into three or more households.

The net result was that 18,249 households were approached to complete the SIH.

Responding Households and final sample

In scope households selected for inclusion in the survey can be categorised as responding or non-responding households. Responding households are either fully responding or partially responding. In the SIH, some information missing from partially responding households is imputed, as described in the 'Data Collection and Processing' section of this publication.
Non-responding households include:

• households affected by death or illness of a household member;
• households in which the significant person(s) in the household refused to participate; and
• households in which the significant person(s) did not respond to key questions.

The final sample on which estimates were based, is composed of persons for whom 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 18,249 in the scope of the survey, of which 14,162 (78%) were included as part of the final estimates. The final sample consists of those 14,162 households, comprising 27,339 persons aged 15 years old and over.

Table 1 shows the distribution of the final samples between States and Territories and between Capital City Area and Rest of State.

TABLE 1 SIH FINAL SAMPLE, 2013-14
	GREATER CAPITAL CITY AREA		REST OF STATE		TOTAL
	Households	Persons (a)	Households	Persons (a)	Households	Persons (a)
	no.	no.	no.	no.	no.	no.
NSW	1 471	3 066	1 061	1 985	2 532	5 051
Vic.	1 301	2 715	986	1 836	2 287	4 551
Qld	1 139	2 283	1 132	2 130	2 271	4 413
SA	1 188	2 262	943	1 678	2 131	3 940
WA	1 004	1 999	838	1 565	1 842	3 564
Tas.	622	1 160	1 082	1 922	1 704	3 082
NT	469	930	61	105	530	1 035
ACT	865	1 703	-	-	865	1 703
Aust.	8 059	16 118	6 103	11 221	14 162	27 339
– nil or rounded to zero (including null cells) (a) Number of persons aged 15 years and over