4727.0.55.004 - Australian Aboriginal and Torres Strait Islander Health Survey: Physical activity, 2012-13  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 05/12/2014  First Issue
   Page tools: Print Print Page Print all pages in this productPrint All

EXPLANATORY NOTES

INTRODUCTION


1 This publication presents a selection of results from the 2012-13 Australian Aboriginal and Torres Strait Islander Health Survey (AATSIHS) with the focus on physical activity, sedentary behaviour and pedometer steps. Collectively AATSIHS encompasses the following three components of the Aboriginal and Torres Strait Islander sample that forms part of the wider ABS Australian Health Survey (AHS) programme:

  • The National Aboriginal and Torres Strait Islander Health Survey (NATSIHS)
  • The National Aboriginal and Torres Strait Islander Nutrition and Physical Activity Survey (NATSINPAS)
  • The National Aboriginal and Torres Strait Islander Health Measures Survey (NATSIHMS).

2 Results in this publication are from either a combined data file of both the NATSIHS and NATSINPAS, referred to as the AATSIHS Core, or from the NATSINPAS only. The combined sample size of the AATSIHS Core (12,947 Aboriginal and Torres Strait Islander people) is around 3.2 times the 2012-13 NATSINPAS sample and may therefore produce more accurate estimates. However, the AATSIHS Core sample only contains those data items common to both NATSIHS and NATSINPAS, and therefore does not provide the full spectrum of data items from the AATSIHS. As a result, items for adults, pedometer and 2-4 year olds has been sourced from NATSINPAS only. For more information see: The Structure of the AATSIHS
    3 As this release covers two data sources, where appropriate, separate information has been provided on both the AATSIHS Core and NATSINPAS only in the paragraphs that follow.

    4 The AATSIHS Core incorporated surveys which were conducted throughout Australia from April 2012 to July 2013. The NATSINPAS component was conducted throughout Australia from August 2012 to July 2013. The NATSIHS collected similar data on adult physical activity as NATSINPAS, of which level of exercise was reported in the Australian Aboriginal and Torres Strait Islander Health Survey: First Results, 2012-13 (cat no. 4727.0.55.001).

    5 This publication contains information about physical activity (including pedometer steps) and sedentary behaviour (in particular screen-based activity, household rules and screen-based equipment) and comparisons with:
    • demographic characteristics
    • health-related aspects of people’s lifestyles, such as Body Mass Index and fruit and vegetable intake

    6 Throughout this release, the term 'Aboriginal and Torres Strait Islander people' refers to all persons who identified themselves as being of Aboriginal, Torres Strait Islander, or both Aboriginal and Torres Strait Islander origin.
      7 This release also includes data cubes that enable comparisons with the non-Indigenous non-remote population of the 2011-12 National Nutrition and Physical Activity Survey (NNPAS) component of the 2011–13 Australian Health Survey. The data for remote and non-remote Aboriginal and Torres Strait Islander populations within the data cubes are not comparable.

      8 Explanations of terms and concepts are provided in the Glossary and a list of data items currently available from the survey can be found in the Australian Aboriginal and Torres Strait Islander Health Survey: Users’ Guide, 2012-13 (cat no. 4727.0.55.002), referred to throughout this publication as the 'Users' Guide'.

      SCOPE AND COVERAGE OF THE SURVEY

      9 The AATSIHS Core contains a sample of 8,237 private dwellings across Australia, while the NATSINPAS contains a sample of 2900 private dwellings. Private dwellings are houses, flats, home units and any other structures used as private places of residence at the time of the survey. People usually resident in non-private dwellings, such as hotels, motels, hostels, hospitals, nursing homes, and short-stay caravan parks were not in scope.

      10 The scope of the AATSIHS Core and NATSINPAS was all Aboriginal and Torres Strait Islander people who were usual residents of private dwellings in Australia. Usual residents are those who usually live in a particular dwelling and regard it as their own or main home.

      11 Further scope exclusions for these surveys were:
      • Non-Indigenous persons;
      • Non-Australian diplomats; diplomatic staff and members of their household;
      • Members of non-Australian Defence forces stationed in Australia and their dependents; and
      • Overseas visitors.
        12 The survey excluded visitors to private dwellings, except for those that had been resident six months or longer. Visitors who were a usual resident of another dwelling and were in-scope of the survey may be selected in the survey only at their usual residence dwelling, or if not selected, would have been represented by similar persons who were selected in the survey.

        13 The AATSIHS Core and NATSINPAS were conducted in remote and non-remote areas in all states and territories of Australia, including discrete Aboriginal and Torres Strait Islander communities.

        14 Coverage exclusions apply to those people who were part of the in-scope population, but who were not included in the sampling frame as a result of managing enumeration costs. The sample was based on where Aboriginal and Torres Strait Islander households were identified in the 2011 Census of Population and Housing. Coverage exclusions applied included:
        • Statistical Areas Level 1 (SA1s) (or Collection Districts (CDs) in the Northern Territory (NT)) with no Aboriginal and Torres Strait Islander households;
        • Some discrete Aboriginal and Torres Strait Islander communities with a small number of Aboriginal and Torres Strait Islander households; and
        • Some SA1s, or CDs in the NT, in remote areas with a small number of Aboriginal and Torres Strait Islander households.
          15 These coverage exclusions result in an estimated undercoverage of approximately 4% of Aboriginal and Torres Strait Islander persons in Australia. Although these areas were not enumerated, the final sample was weighted to population benchmarks to account for these exclusions. Further information on undercoverage is provided in paragraphs 42 to 46 and more information on the scope and coverage of the survey is provided in the Users' Guide.

          16 The estimated resident Aboriginal and Torres Strait Islander population aged 2 years and over living in private and non-private dwellings at 30 June 2011 was 636,945. Excluding persons in non-private dwellings, there were 606,915 Aboriginal and Torres Strait Islander people aged 2 years and over.

          17 Population benchmarks, which align with the survey scope, are based on the most recently released Estimated Resident Aboriginal and Torres Strait Islander Population (ERP), which in this case are for 30 June 2011. The ERP data are based on the 2011 Census of Population and Housing, adjusted by the 2011 Post-Enumeration Survey (PES). More information about the Estimated Resident Aboriginal and Torres Strait Islander Population can be found in Estimates of Aboriginal and Torres Strait Islander Australians, June 2011 (cat. no. 3238.0.55.001).

          RESPONSE RATES

          18 The AATSIHS Core approached 10,362 households, after sample loss. Of these, 8,237 (or 80%) were fully or adequately responding, yielding a total sample for the survey of 12,947 persons (aged 2 years and over). The NATSINPAS approached 3,661 households after sample loss. Of these, 2,900 (79%) were fully or adequately responding, yielding a total sample for the survey of 4,109 persons (aged 2 years and over).
            19 The final persons in sample used in the publication by non-remote and remote follow.
            FINAL PERSONS IN SAMPLE

            Non-remoteRemote

            Adults1170(a)3608
            Children
            2-4(a)145Not applicable
            5-1722071489
            Pedometer(a)(b)
            Child 5-17124Not applicable
            Adult403Not applicable

            (a) NATSINPAS only
            (b) for those meeting a four day (including one week day and one weekend day) reporting threshold requirement only


            20 More information on response rates is available in the Users' Guide.

            DATA COLLECTION

            21 Trained ABS interviewers conducted personal interviews with selected residents in sampled dwellings. Selected persons aged 18 years and over in each dwelling were interviewed about their own health characteristics. An adult, nominated by the household, was interviewed for selected children (aged 2 years and over) in the household. Selected children aged 15-17 years may have been personally interviewed with parental consent. An adult, nominated by the household, was also asked to provide information about the household, such as the combined income of other household members. Children aged 6-14 years were encouraged to be involved in the survey, particularly for the physical activity module (see Child Physical Activity (5 to 17 years) chapter in the Users' Guide).
              22 Aboriginal and Torres Strait Islander persons aged 15–17 years could choose to have their interview completed by a parent or guardian. 37% of interviews were conducted by proxy for this age group in the AATSIHS Core, and 39% in the NATSINPAS.
                23 All selected persons in non-remote areas of the NATSINPAS were asked to have a follow-up telephone interview at least 8 days after the face to face interview to collect further nutrition data. For those who opted in, pedometer data was also reported during this telephone interview.
                  24 The physical measures module of the AATSIHS Core and NATSINPAS was voluntary. In 2012-13, 82% of respondents in the AATSIHS Core aged 2 years and over had their height and weight measured. As a proportion of the Australian weighted population, 82% of persons aged 2 years and over had a height and weight measurement. For the NATSINPAS, 86% of respondents aged 2 years and over had their height and weight measured. As a proportion of the Australian weighted population, 84% of persons aged 2 years and over in the NATSINPAS had a height and weight measurement. BMI data presented in this publication relates to the measured population only. Analysis of the characteristics of people who agreed to be measured compared to those who declined across the AATSIHS suite of surveys indicated that age and remoteness were factors in non-response. Persons in non-remote areas were more likely to decline and response was higher amongst the 18 years and over than the under 18 year olds.
                    25 In 2012-13, 89% of NATSINPAS respondents aged 18 years and over agreed to have their blood pressure measured and had a valid blood pressure reading obtained. As a proportion of the Australian weighted population, this represented 88% of persons aged 18 years and over. Note that persons 5 years and over also had valid blood pressure readings collected, however data presented in this publication relates to the measured adult population only from NATSINPAS.
                      26 Of respondents aged 5 years and over in non-remote areas, 37% participated in the pedometer component of the NATSINPAS, and 31% met the pedometer day threshold for use in the reporting of selected items (see Pedometer Steps chapter of the Users' Guide). Therefore, pedometer steps data presented in this publication relates to the population that met this threshold. Analysis of the characteristics of people who participated in the pedometer component compared to those who declined indicated that state, remoteness area, and employment status were factors in non-response. However these differences are not associated to the pedometer variables, indicating that any potential non-response bias is likely to be small. Further analysis indicated that an adjustment or an additional weight was not required in order to produce representative pedometer steps proportion data.

                      27 To take account of language and cultural differences in community areas, the collection method varied for remote and non-remote areas. Some questions for remote areas, for example the physical activity module, were reworded to enhance respondent understanding of the concepts. Additionally, the survey content in remote areas excluded questions for which data quality was considered problematic to collect or not applicable.

                      28 More information on data collection and a copy of the survey questionnaires are provided in the Users' Guide.

                      WEIGHTING, BENCHMARKING AND ESTIMATION

                      29 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 person. The weight is a value which indicates how many population units are represented by the sample unit.

                      30 The first step in calculating weights for each person is to assign an initial weight, which is equal to the inverse of the probability of being selected in the survey. For example, if the probability of being selected in the survey was 1 in 45, then the person would have an initial weight of 45 (that is, they would represent 45 people).

                      31 The weights were separately calibrated to 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 distributions 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 (e.g. age, sex, remoteness), which may occur due to either the random nature of sampling, non-response, non-identification or various other factors.
                        32 The survey was benchmarked to the estimated Aboriginal and Torres Strait Islander resident population living in private dwellings at 30 June, 2011. As people in non-private dwellings (e.g. hotels) are excluded from the scope of the survey, they have also been excluded from the survey benchmarks. Therefore, the AATSIHS Core and the NATSINPAS estimates do not (and are not intended to) match estimates for the total resident Aboriginal and Torres Strait Islander population obtained from other sources.

                        33 Estimates of counts of persons are obtained by summing person weights of persons with the characteristic of interest. The estimates presented in this release are based on benchmarked person weights.

                        34 More information on weighting, benchmarking and estimation is provided in the Users' Guide.

                        RELIABILITY OF ESTIMATES

                        35 All sample surveys are subject to error which can be broadly categorised as either sampling error or non-sampling error.

                        36 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. For more information refer to the Technical Note. Indications of the level of sampling error are given by the Relative Standard Error (RSE) and Margin of Error (MoE).

                        37 In this publication, estimates with an RSE of 25% to 50% are preceded by an asterisk (e.g. *3.4) 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 indicated by a double asterisk (e.g. **0.6) and are generally considered too unreliable for most purposes. These estimates can be used to aggregate with other estimates to reduce the overall sampling error.

                        38 MoEs, calculated at the 95% confidence level, are provided for all proportion estimates to assist users in assessing the reliability of these types of estimates. Users may find this measure more convenient to use than the RSE, in particular for small and large proportions. The estimate 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 estimate. In this publication, proportions with a MoE greater than 10 percentage points are preceded by a hash (e.g. #71.3).

                        39 Non-sampling error may occur in any data collection, whether it is based on a sample or a full count (e.g. Census). Non-sampling error may occur at any stage throughout the survey process. For example, persons selected for the survey may not respond (non-response); survey questions may not be clearly understood by the respondent; responses may be incorrectly recorded by interviewers; or there may be errors in coding or processing data.
                          40 Non-response occurs when people cannot or will not cooperate, 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.

                          41 Analysis was also undertaken, where appropriate, to compare the characteristics of respondents to the AATSIHS Core and the NATSINPAS with a number of ABS collections to ascertain data consistency. Sources for comparison included:
                          • 2011 Census of Population and Housing
                          • 2008 National Aboriginal and Torres Strait Islander Social Survey
                          • 2004–05 National Aboriginal and Torres Strait Islander Health Survey.
                            Undercoverage

                            42 Undercoverage is the shortfall between the population represented by the achieved sample and the in-scope population. Weighting, as described in paragraphs 29 to 34 adjusts for undercoverage, reducing the under-coverage bias in estimates.
                              43 Undercoverage rates can be estimated by calculating the difference between the sum of the initial weights of the sample and the population count. If a survey has no undercoverage, then the sum of the initial weights of the sample would equal the population count (ignoring small variations due to sampling error).

                              44 It is usual for ABS Aboriginal and Torres Strait Islander surveys to have large levels of undercoverage. The AATSIHS Core and the NATSINPAS undercoverage rate was 63% of the in-scope population at the national level. However, 6% of this is due to planned frame exclusions and overlap with the Monthly Population Survey where analysis has shown that the impact of any bias is minimal. For comparison, the estimated undercoverage in the 2004–05 NATSIHS and the 2008 NATSISS was 42% and 53% respectively.

                              45 The NATSINPAS rate varies across states and territories, with Vic (78%), NT (72%) and NSW (68%) recording the highest rates of undercoverage compared with the lowest undercoverage rates in Tas (6%) and ACT (44%). AATSIHS Core rates can be found in the Users' Guide.
                                46 Undercoverage may occur due to a number of factors, including:
                                • frame exclusions (areas being removed from the sampling frame);
                                • non-response;
                                • non-identification as being of Aboriginal and/or Torres Strait Islander origin; and
                                • issues arising in the field
                                  For more details on these, refer to the Users' Guide.

                                  CLASSIFICATIONS

                                  47 The classifications used to describe adult and child physical activity in this publication used the same classifications as in NNPAS, which were developed based on other ABS surveys:
                                  48 Descriptions for data items such as Body Mass Index and blood pressure are included in the Glossary to this publication.
                                    49 Geography data, including Remoteness Area, was classified according to the Australian Statistical Geographical Standard (ASGS), July 2011 (cat. no. 1270.0.55.001).
                                      CONFIDENTIALITY
                                        50 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.

                                        51 Some techniques used to guard against identification or disclosure of confidential information in statistical tables are suppression of sensitive cells, random adjustments to cells with very small values, and aggregation of data. To protect confidentiality within this publication, some cell values may have been suppressed and are not available for publication but included in totals where applicable. As a result, sums of components may not add exactly to totals due to the confidentialisation of individual cells.

                                        ROUNDING

                                        52 Estimates presented in this publication have been rounded. As a result, sums of components may not add exactly to totals.

                                        53 For physical activity data in this publication, minutes and average number of steps are reported as whole numbers. All other units in the data are reported to one decimal place.

                                        54 Proportions presented in this publication are based on unrounded figures. Calculations using rounded figures may differ from those published.

                                        ACKNOWLEDGMENTS

                                        55 The AATSIHS Core and the NATSINPAS was dependent on the high level of cooperation received from Aboriginal and Torres Strait Islander peoples and their communities. Without their continued cooperation, the wide range of Aboriginal and Torres Strait Islander 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

                                        56 Further Australian Aboriginal and Torres Strait Islander Health Survey (AATSIHS) publications are planned for release. For more information see Release schedule.

                                        57 Information from the AATSIHS Core and the NATSINPAS will be returned to Aboriginal and Torres Strait Islander people through the ABS State and Territory Statistical Services (STSS) Program and collaborations with other organisations.

                                        58 Special tabulations based on the data from this survey are available on request. Subject to confidentiality and sampling variability constraints, tabulations can be produced from the survey to meet individual requirements. These can be provided in electronic or printed form.
                                          59 For users who wish to undertake more detailed analysis of the survey data, TableBuilder and an Expanded CURF will also be made available in 2015. TableBuilder is an online tool for creating tables from ABS survey data, where variables can be selected for cross-tabulation. It has been developed to complement the existing suite of ABS microdata products and services including Census TableBuilder and CURFs. Further information about ABS microdata, including conditions of use, is available via the Microdata section on the ABS web site.

                                          60 For more information about this survey and associated products contact the National Information and Referral Service on 1300 135 070 or the National Centre for Aboriginal and Torres Strait Islander Statistics on indigenous.statistics@abs.gov.au. The ABS Privacy Policy outlines how the ABS will handle any personal information that you provide to us.

                                          RELATED PUBLICATIONS

                                          61 Other ABS publications which may be of interest are shown under the 'Related Information' tab of this release.

                                          62 Current publications and other products released by the ABS are listed on the ABS website <www.abs.gov.au>. The ABS also issues a daily Release Advice on the website which details products to be released in the week ahead.