Notes on the data: Health risk factors

Estimated male, female or total population, aged 2 to 17 years, who were obese or overweight, 2014-15


Policy context:   Overweight and obesity in childhood and adolescence can cause a range of physical and emotional health problems; and obesity increases the risk of chronic disease and premature death in adulthood. In 2014-15, around one in four (27.4%) children and young people aged 5-17 years were overweight or obese, comprised of 20.2% overweight and 7.4% obese. There has been no change since 2011-12 (25.7%) in the proportion of children and young people who were overweight or obese [1].


  1. Australian Bureau of Statistics (ABS). Children’s Risk Factors, National Health Survey: First Results, 2014-15. Available from:; last accessed 04/12/2016

Notes:  In the absence of data from administrative data sets, estimates are provided for selected health risk factors from the 2014–15 National Health Survey (NHS), conducted by the Australian Bureau of Statistics (ABS).

Estimates at the Population Health Area (PHA) are modelled estimates produced by the ABS, as described below (estimates at the Local Government Area (LGA) and Primary Health Network (PHN) level were derived from PHA estimates).

Users of these modelled estimates should note that they do not represent data collected in administrative or other data sets. As such, they should be used with caution, and treated as indicative of the likely social dimensions present in an area with these demographic and socioeconomic characteristics.

The numbers are estimates for an area, not measured events as are, for example, death statistics. As such, they should be viewed as a tool that, when used in conjunction with local area knowledge and taking into consideration the prediction reliability, can provide useful information that can assist with decision making for small geographic regions. Of particular note is that the true value of the published estimates is also likely to vary within a range of values as shown by the upper and lower limits published in the data (xls) and viewable in the bar chart in the single map atlases.

What the modelled estimates do achieve, however, is to summarise the various demographic, socioeconomic and administrative information available for an area in a way that indicates the expected level of each health indicator for an area with those characteristics. In the absence of accurate, localised information about the health indicator, such predictions can usefully contribute to policy and program development, service planning and other decision-making processes that require an indication of the geographic distribution of the health indicator.

The survey response rate of around 85% provides a high level of coverage across the population; however, the response rate is lower than among other groups, e.g., those living in the most disadvantaged areas have a lower response rate than those living in less disadvantaged areas. Although the sample includes the majority of people living in households in private dwellings, it excludes those living in the most remote areas of Australia; whereas these areas comprise less than 3% of the total population, Aboriginal people comprise up to one third of the population in these areas. This and other limitations of the method mean that estimates have not been published for PHAs with populations under 1,000, or with a high proportion of their population in:

  1. non-private dwellings (hospitals, gaols, nursing homes - and also excludes members of the armed forces);
  2. in very remote or in discrete Aboriginal communities, as determined by the ABS; and
  3. where the relative root mean square errors (RRMSEs) on the estimates was 1 or more (estimate replaced with ≠)


  1. Estimates with RRMSEs from 0.25 and to 0.50 have been marked (~) to indicate that they should be used with caution; and those greater than 0.50 but less than 1 are marked (~~) to indicate that the estimate is considered too unreliable for general use.
  2. For the Primary Health Network (PHN) data, differences between the PHN totals and the sum of LGAs within PHNs result from the use of different concordances.

Indicator detail

The Body Mass Index (BMI) (or Quetelet's index) is a measure of relative weight based on an individual's mass and height. The height (cm) and weight (kg) of respondents, as measured during the NHS interview, were used to calculate the BMI – details at; last accessed 04/12/2016

Note that the modelled estimates are based on the 62.3% of children and young people aged 2 to 17 years in the sample who had their height and weight measured. For respondents who did not have their height and weight measured, imputation was used to obtain height, weight and BMI scores. For more information see Appendix 2: Physical measurements in the National Health Survey in the ABS publication National Health Survey: First Results, 2014-15 (Cat. no. 4364.0.55.001).


Geography: Data available by Population Health Area, Local Government Area, Primary Health Network, Quintiles and Remoteness Areas

Numerator:  Estimated number of males, females or persons aged 2 to 17 years who were assessed as being overweight (not obese) or obese, based on their measured height and weight


Denominator:  Male, female or total population aged 2 to 17 years


Detail of analysis:  Indirectly age-standardised rate per 100 males, females or persons (aged 2 to 17 years); and/or indirectly age-standardised ratio, based on the Australian standard


Source:  Compiled by PHIDU based on modelled estimates from the 2014-15 National Health Survey, ABS (unpublished).


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