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National Healthcare Agreement: PI 03-Prevalence of overweight and obesity, 2017 QS

Identifying and definitional attributes

Metadata item type:Help on this termQuality Statement
METeOR identifier:Help on this term658459
Registration status:Help on this termHealth, Standard 31/01/2017

Relational attributes

Indicators linked to this Quality statement:Help on this term

National Healthcare Agreement: PI 03–Prevalence of overweight and obesity, 2017 Health, Superseded 30/01/2018

Data quality

Institutional environment:Help on this term

The 2014–15 National Health Survey (NHS) was collected, processed, and published by the Australian Bureau of Statistics (ABS). The ABS operates within a framework of the Census and Statistics Act 1905 and the Australian Bureau of Statistics Act 1975. These ensure the independence and impartiality from political influence of the ABS, and the confidentiality of respondents.

For more information on the institutional environment of the ABS, including the legislative obligations of the ABS, financing and governance arrangements, and mechanisms of scrutiny of ABS operations, see ABS institutional environment.

Timeliness:Help on this term

The NHS is conducted approximately every 3 years. The 2014–15 NHS was conducted between July 2014 and June 2015. The previous NHS was collected as part of the Australian Health Survey (AHS) in 2011–13. Results from the 2014–15 NHS were released in December 2015.

Accessibility:Help on this term

See National Health Survey: first results, 2014–15 (ABS 2015) for an overview of results. Other information from this survey may also be available on request.

Interpretability:Help on this term

Information to aid interpretation of the data from the National Health Survey: first results, 201415 (ABS 2015) is available on the ABS website.

Many health-related issues are closely associated with age; therefore data for this indicator have been age-standardised to the 2001 total Australian population to account for differences in the age structures of the states and territories. Age-standardised rates should be used to assess the relative differences between groups, not to infer the rates that actually exist in the population.

Relevance:Help on this term

The 2014–15 NHS collected measured height and weight from persons aged 2 years and over. (Note that for this indicator, children are defined as persons aged 5–17 years.) For the purposes of this indicator, body mass index (BMI) values are derived from measured height and weight information using the formula: weight (kg) / height (m)2.

Despite some limitations, BMI is widely used internationally as a relatively straightforward way of measuring overweight and obesity.

Accuracy:Help on this term

The 2014–15 NHS was conducted in all states and territories, excluding Very remote areas and discrete Aboriginal and Torres Strait Islander communities. These exclusions are unlikely to affect national estimates, and will only have a minor effect on aggregate estimates produced for individual states and territories, excepting the Northern Territory where the population living in private dwellings in Very remote areas accounts for around 28% of persons. Non-private dwellings such as hotels, motels, hospitals, nursing homes and short-stay caravan parks were also excluded from the survey. The response rate for the 2014–15 NHS was 82%. Results are weighted to account for non-response.

As they are drawn from a sample survey, data for the indicator are subject to sampling error. Sampling error occurs because only a small proportion of the population is used to produce estimates that represent the whole population. Sampling error can be reliably estimated as it is calculated based on the scientific methods used to design surveys. Indications of the level of sampling error are given by the relative standard error (RSE) and 95% margin of error (MOE). Estimates with an RSE of 2550% should be used with caution. Estimates with an RSE over 50% are generally considered too unreliable for general use. Margins of error are provided for proportions to assist 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. Proportions with an MOE of greater than 10 percentage points indicate that the range in which the true population value is expected is relatively wide.

The following comments apply to data for the general and non-Indigenous populations only:

  • in 2014–15, 26.8% of respondents aged 18 years and over and 37.7% of respondents aged 2–17 years did not have their height, weight or both measured. For these people, height and weight were imputed. For more information see Appendix 2: Physical measurements in the 2014–15 National Health Survey (ABS 2015)
  • results for all physical measurement data (BMI, waist circumference and blood pressure) from the 2014–15 NHS are of suitable quality and are directly comparable to 2011–12 and earlier years.

Adult BMI rates by state/territory (Table NHA 3.1):

  • RSEs for underweight for South Australia, Tasmania, the Australian Capital Territory and the Northern Territory are greater than 25% and data should be used with caution.

Child BMI rates by state/territory (Table NHA 3.1):

  • RSEs for underweight for New South Wales, Victoria, South Australia, Tasmania and the Northern Territory, and underweight and obese for the Australian Capital Territory, are greater than 25% and data should be used with caution.

Adult overweight and obesity rates by state/territory and remoteness (Table NHA 3.2):

  • RSEs for Remote New South Wales, Victoria, Queensland, South Australia and Tasmania are greater than 50% and data are considered too unreliable for general use.

Child overweight and obesity rates by state/territory and remoteness (Table NHA 3.2):

  • RSEs for Inner regional New South Wales, Queensland, Western Australia and South Australia, Outer regional New South Wales and South Australia, and total Remote Australia, are greater than 25% and data should be used with caution.
  • RSEs for Outer regional Victoria and Western Australia, and Remote New South Wales, Queensland and South Australia, are greater than 50% and data are considered too unreliable for general use.

Adult overweight and obesity rates by state/territory and Socio-economic Indexes for Areas (SEIFA) quintiles (Table NHA 3.3):

  • The RSE for quintile 1 in the Australian Capital Territory is greater than 25% and data should be used with caution.

Child overweight and obesity rates by state/territory and SEIFA quintiles (Table NHA 3.3):

  • RSEs for quintiles 2 and 4 in South Australia, quintiles 3 and 4 in Tasmania and the Australian Capital Territory, and quintile 4 in the Northern Territory, are greater than 25% and data should be used with caution.
  • RSEs for quintile 5 in South Australia and Tasmania, quintile 2 in the Australian Capital Territory, and quintiles 1, 2 and 5 in the Northern Territory, are greater than 50% and data are considered too unreliable for general use.

Adult overweight and obesity rates by state/territory and sex and age (Table NHA 3.4):

  • RSEs for females aged 18–24 and 70–74 years in the Northern Territory are greater than 25% and data should be used with caution.
  • The RSE for males aged 75 and over in the Northern Territory is greater than 50% and data are considered too unreliable for general use.
Coherence:Help on this term

The methods used to construct the indicator are consistent and comparable with other collections and with international practise.

Most surveys, including computer-assisted telephone interviewing health surveys conducted by the states and territories, collect only self-reported height and weight. There is a general tendency across the population for people to overestimate height and underestimate weight, which results in BMI scores based on self-reported height and weight to be lower than BMI scores based on measured height and weight.

The age- and sex-specific cut off points for BMI categories for children are from the work of Cole et al. (2000).

The 2014–15 NHS collected a range of other health-related information that can be analysed in conjunction with BMI.

Source and reference attributes

Submitting organisation:Help on this term

Australian Bureau of Statistics

Reference documents:Help on this term

ABS (Australian Bureau of Statistics) 2015. National Health Survey: first results, 2014-15. ABS cat. no. 4364.0.55.001. Canberra: ABS.

Cole TJ, Bellizzi MC, Flegal KM & Dietz WH 2000. Establishing a standard definition for child overweight and obesity worldwide: international survey. BMJ 320:240.

Relational attributes

Related metadata references:Help on this term

Supersedes National Healthcare Agreement: PI 03-Prevalence of overweight and obesity, 2015 QS Health, Superseded 31/01/2017

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