Crowd-Out and Emergency Department Utilization

49 Pages Posted: 4 Aug 2018 Last revised: 23 Mar 2023

Date Written: July 16, 2018


A policy proposal to address the over-use of emergency departments by the uninsured is expanding public insurance. However, the uninsured are typically not the only recipients of expansions -- crowd-out occurs, and the two groups face radically different price changes. Using the Low Income Health Program in California, we examine how the prior insurance status of the newly eligible Medicaid population impacts emergency department usage. We use machine learning to estimate crowd-out and find utilization increased, but this increase was driven entirely by those crowded-out from private insurance. This has increased healthcare expenditures in California by $329.6 million per year.

Keywords: Crowd Out, Emergency Departments, Medicaid, Public Insurance, Machine Learning

JEL Classification: I13, I18, I38, G22

Suggested Citation

Ellis, Cameron and Esson, Meghan, Crowd-Out and Emergency Department Utilization (July 16, 2018). Fox School of Business Research Paper No. 18-038, Available at SSRN: or

Cameron Ellis

University of Iowa ( email )

Tippie College of Business
21 E Market st
Iowa City, IA 52246
United States

Meghan Esson (Contact Author)

University of Iowa ( email )

Iowa City, IA 52242-1000
United States

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