Department or Program


Primary Wellesley Thesis Advisor

Kristin Butcher

Additional Advisor(s)

Patrick McEwan


Obesity status, which is based on arbitrary cutoffs along the BMI distribution, is a salient feature of medical charts and may be used heuristically by physicians to decide whether to test their patients for obesity-related diseases. Using nationally representative datasets and a regression discontinuity design, I explore whether there are differences in diagnosis and treatment outcomes among individuals very close to the obesity cutoff at BMI=30, assuming no underlying differences in health. I find evidence that women above the obesity threshold are significantly less likely to be told they are diabetic, have high blood pressure, or have coronary heart disease. Men just above the obesity threshold are more likely to be told they have a heart condition, but are less likely to report being advised by their physicians to change their behaviors to reduce risk of developing heart disease. These results suggest physicians use the obesity threshold heuristically, which could have detrimental implications for subsequent health outcomes: individuals below the threshold could be under-treated, while individuals above it may be over-treated. The prevalence and effects of heuristics in medicine should be investigated more thoroughly to improve physician-patient interactions and subsequent health outcomes.