Volume 54 | Number 4 | August 2019

Abstract List

Charleen Hsuan JD, PhD, Renee Y. Hsia M.D., M.Sc., Jill R. Horwitz, Ninez A. Ponce Ph.D., M.P.P., Thomas Rice, Jack Needleman


To examine whether hospitals are more likely to temporarily close their emergency departments (s) to ambulances (through ambulance diversions) if neighboring diverting hospitals are public vs private.

Data Sources/Study Setting

Ambulance diversion logs for California hospitals, discharge data, and hospital characteristics data from California's Office of Statewide Health Planning and Development and the American Hospital Association (2007).

Study Design

We match public and private (nonprofit or for‐profit) hospitals by distance and size. We use random‐effects models examining diversion probability and timing of private hospitals following diversions by neighboring public vs matched private hospitals.

Data Collection/Extraction Methods


Principal Findings

Hospitals are 3.6 percent more likely to declare diversions if neighboring diverting hospitals are public vs private (<0.001). Hospitals declaring diversions have lower occupancy (<0.001) after neighboring public (vs private) hospitals divert. Hospitals have 4.2 percent shorter diversions if neighboring diverting hospitals are public vs private (<0.001). When the neighboring hospital ends its diversion first, hospitals terminate diversions 4.2 percent sooner if the neighboring hospital is public vs private (=0.022).


Sample hospitals respond differently to diversions by neighboring public (vs private) hospitals, suggesting that these hospitals might be strategically declaring ambulance diversions to avoid treating low‐paying patients served by public hospitals.