OUTPUT PROCESSING


Information from the questionnaire, other than names and addresses, was stored on a computer output file in the form of data items. In some cases, items were formed from answers to individual questions, while in other cases data items were derived from answers to several questions.

During processing of the data, checks were performed on records to ensure that specific values lay within valid ranges and that relationships between items were within limits deemed acceptable for the purposes of this survey. These checks were also designed to detect errors which may have occurred during processing and to identify instances which, although not necessarily an error, were sufficiently unusual or close to agreed limits to warrant further examination.

Throughout processing, frequency counts and tables containing cross-classifications of selected data items were produced for checking purposes. The purpose of this analysis was to identify any problems in the input data which had not previously been identified, as well as errors in derivations or other inconsistencies between related items.

Output file

A multi-level hierarchical data file was produced, containing the following levels:

1. Household
3. Person
4. Barriers

The contents of each level are briefly described below:

• Person level—contains the majority of information on the respondent, including demographic and socio-economic characteristics (eg age, sex, marital status, education, labour force status, personal income), language and culture, health, social capital, crime and safety, information technology, transport etc;
• Household level—contains information on the household and its members, collected in the household form, including family composition of household, household structure, number of persons/children in household, household income, dwelling tenure type, etc; and
• Barriers level—contains information about the types of services that were difficult to access and the reasons why they were described as difficult. See the Stressors chapter for more information on the Barriers level.

An additional level (2. All persons in household) was created for processing purposes, including family coding and calculating household income. Data from this level is not available for output.

Most data from the NATSISS is available at the person level and describes personal characteristics, or characteristics of the household to which the person belongs.

Validation checks

The output data file was extensively validated through item-by-item examination of input and output frequencies, checking populations through derivations, internal consistency of items and across levels of the file, data confrontation, etc. Despite these checks, it is possible that some small errors remain undetected on the file.

As a result of the validation processes, some adjustments have been made to data on a record-by-record basis. Changes were done with reference to other information provided by respondents and only to correct clear errors that were not identified during the survey interview, for example, where the reported amount of time lived in previous and/or current dwelling is inconsistent with a person's age. Adjustments may also have occurred as the result of an edit not being applied or being by-passed. For example, where the response to a question was recorded as 'don't know' and was subsequently answered. In cases where the interviewer did not or was unable to return to the original question, the details may have been recorded in a text file.

In general, unless data were 'impossible' they have not been corrected, and results are essentially 'as reported'. To hide 'improbable' responses (eg extremely high alcohol consumption or income) some outliers have been reclassified, primarily to 'not stated' values. Some of these adjustments were made record-by-record; for others a global change was used for all records where reported values lay outside acceptable limits.

Decisions to apply treatments or adjustments to the data were made, as appropriate, by the ABS.

Data confrontation

In the final stages of processing, extensive analyses, including data confrontation, were undertaken to ensure the survey estimates conformed to known or expected patterns, and were broadly consistent with data from the 2008 NATSISS or from other ABS data sources, allowing for methodological and other factors which might impact comparability.

Detailed analyses were undertaken for each topic to check for consistency with data from the following sources:

• 2011 Census of Population and Housing;
• 2008 National Aboriginal and Torres Strait Islander Social Survey;
• 2012–13 Australian Aboriginal and Torres Strait Islander Health Survey;
• 2014 General Social Survey; and
• 2014–15 National Health Survey.

Checks undertaken include:

• comparison of estimates between sources;
• looking at changes over time where items were comparable with other sources; and
• comparisons of estimates by geographic region.

Data available from the survey are essentially 'as reported' by respondents. The procedures and checks outlined above were designed primarily to minimise errors occurring during processing. In some cases it was possible to correct errors or inconsistencies in the data which was originally recorded in the interview, through reference to other data in the record; in other cases this was not possible and some errors and inconsistencies may remain on the data file.

Perturbation

Published NATSISS data have been subject to perturbation. For more information, see Methodology in this publication. For further details relating to the perturbation of Expanded CURF data, see Using the Expanded CURF in the NATSISS microdata publication.