Analyzing data spanning three decades covering the near universe of births, we study county-level differences in Cesarean section (C-section) rates among first-time mothers of singleton births. Our research reveals persistent geographic variation in C-section rates for both low- and high-risk groups. Counties with elevated C-section rates consistently perform more C-sections across mothers at all levels of appropriateness for the procedure. These elevated rates of C-section in high C-section counties are associated with reduced maternal and infant morbidity. We also find that C-section decisions are less responsive to underlying risks for Black mothers relative to white mothers, suggesting potential welfare-reducing disparities.

We study a 2008 policy reform in which Medicare revised its hospital payment system to better reflect patients’ severity of illness. We construct a simulated instrument that predicts a hospital’s policy-induced change in reimbursement using pre-reform patients and postreform rules. The reform led to large persistent changes in Medicare payment rates across hospitals. Hospitals that faced larger gains in Medicare reimbursement increased the volume of Medicare patients they treated. The estimates imply a volume elasticity of 1.2. To accommodate greater volume, hospitals increased nurse employment, but also lowered length of stay.