Exhibit 4.

Estimated Annual Cost Savings, By Scenarios Of Changes In Emergency Medical Services (EMS) Transport Patterns For Patients Not Meeting National Field Triage Guidelines

Scenario	Annual savings in study regions
	Using full study sample for estimates		Using only nonfield activations for estimates
	Dollars	% of acute care costs	Dollars	% of acute care costs
1: All nonfield activations transported to nontrauma centers	136,718,910	40.6	113,365,667	33.7
2: Nonfield activations previously transported to level 1 trauma centers transported to level 2 centers	60,075,703	17.8	60,118,625	17.8
3: Nonfield activations previously transported to level 1 trauma centers transported to nontrauma centers	118,234,110	35.1	100,593,442	29.9
4: Nonfield activations previously transported to level 2 trauma centers transported to nontrauma centers	18,484,800	5.5	12,772,225	3.8
5: 50% of nonfield activations previously transported to level 1 or 2 trauma centers transported to nontrauma centers	67,353,875	20.0	55,677,254	16.5

SOURCE Authors’ analysis of the study data.

NOTES “Nonfield activations” are injured patients who do not meet the criteria in the national field triage guidelines (see Note 17 in text). Cost savings were estimated from average adjusted cost differences by trauma center type (level 1, level 2, and nontrauma centers) after costs of interhospital transfer (including initial emergency department evaluation) for undertriaged patients (those with severe injuries originally transported to nontrauma centers) were accounted for.