Time Trends by Sex in the Misreporting of Body Weight

Amelia R. Branigan, Cornell University

I use data from the National Health and Nutrition Examination Survey between 1999 and 2010 to test for a time trend in the bias on self-reporting of body weight, focusing on differences in misreporting by sex. I find a decline in bias among women across the CDC categories of weight, leading to increasingly accurate approximation of measured obesity rates. While men do not report more accurately than women across the spectrum of BMI, they do report more accurately around the cutoff defining obesity. While the findings support the argument that self-reported weight is not a strict proxy for physical measurement, the trend towards self-report producing more accurate estimates of measured obesity rates should be encouraging for researchers working with surveys that collect weight and height only via self-report. They additionally emphasize the need to consider misreporting separately for men and women, as it appears to reflect distinctly different social processes.