Original URL: http://www.theregister.co.uk/2012/03/16/bmi_lies/
Aussie fatties tell fewer porkies
BMI self-reporting less inaccurate over time, but data still wobbly
Australians are less likely to lie about their height and weight than was the case in the past, and exaggerate less about their dimensions, according to a new analysis by the Australian Bureau of Statistics (ABS). But we still tell an unhealthy amount of fibs about our bodies, leading the ABS to a strict regime of statistical exercises to help the nation understand just how gross it has become.
The ABS is interested in the topic because obesity is a significant public health problem. It therefore compared the 1995 National Nutrition Survey (NNS) and the 2007-2008 National Health Survey to see if what people say about their height and weight matched their actual proportions.
The 1995 study was, pardon the pun, full of porkies. 11.4% of women and 11.7% of men ‘fessed up to being obese, but 17.4% and 18.8% actually were obese.
By 2007-2008 that gap had closed. 19.7% of women said they were obese, as did 21.3% of men. Actual numbers were 23.4% and 25.6%. We also stopped exaggerating about our heights quite so much.
The ABS says the fact we’re still telling porkies means that data about obesity is not to be trusted. It therefore advances a few statistical tricks to cut the fat out of the data, so to speak.
The report concludes that while things are getting better, “ … individuals tend to over-report their height and under-report their weight.” The result of those fibs is “under-reporting of BMI and an underestimation of the prevalence of obesity in the population when self-reported figures are used.” ®