NATIONAL BUREAU OF ECONOMIC RESEARCH
NATIONAL BUREAU OF ECONOMIC RESEARCH

Beyond BMI: The Value of More Accurate Measures of Fatness and Obesity in Social Science Research

John Cawley, Richard V. Burkhauser

NBER Working Paper No. 12291
Issued in June 2006
NBER Program(s):   HC   HE

Virtually all social science research related to obesity uses body mass index (BMI), usually calculated using self-reported values of weight and height, or clinical weight classifications based on BMI. Yet there is wide agreement in the medical literature that such measures are seriously flawed because they do not distinguish fat from fat-free mass such as muscle and bone. Here we evaluate more accurate measures of fatness (total body fat, percent body fat, and waist circumference) that have greater theoretical support in the medical literature. We provide conversion formulas based on NHANES data so that researchers can calculate the estimated values of these more accurate measures of fatness using the self-reported weight and height available in many social science datasets.

To demonstrate the benefits of these alternative measures of fatness, we show that using them significantly impacts who is classified as obese. For example, when the more accurate measures of fatness are used, the gap in obesity between white and African American men increases substantially, with white men significantly more likely to be obese. In addition, the gap in obesity between African American and white women is cut in half (with African American women still significantly more likely to be obese).

As an example of the value of fatness in predicting social science outcomes, we show that while BMI is positively correlated with the probability of employment disability in the PSID, when body mass is divided into its components, fatness is positively correlated with disability while fat-free mass (such as muscle) is negatively correlated with disability.

download in pdf format
   (156 K)

email paper

The NBER Bulletin on Aging and Health provides summaries of publications like this.  You can sign up to receive the NBER Bulletin on Aging and Health by email.

This paper is available as PDF (156 K) or via email.

This paper was revised on July 31, 2006

Machine-readable bibliographic record - MARC, RIS, BibTeX

Published: Burkhauser, Richard V., and John Cawley. "Beyond BMI: The Value of More Accurate Measures of Fatness and Obesity in Social Science Research." Journal of Health Economics, March 2008, 27(2): 519-529.

Users who downloaded this paper also downloaded these:
Cawley w7841 Body Weight and Women's Labor Market Outcomes
Wada and Tekin w13595 Body Composition and Wages
Cawley and Spiess w13997 Obesity and Skill Attainment in Early Childhood
Baum and Ruhm w13289 Age, Socioeconomic Status and Obesity Growth
Bleich, Cutler, Murray, and Adams w12954 Why Is The Developed World Obese?
 
Publications
Activities
Meetings
Data
People
About

Support
National Bureau of Economic Research, 1050 Massachusetts Ave., Cambridge, MA 02138; 617-868-3900; email: info@nber.org

Contact Us