EXHIBIT 1.

Comparison of intervention and comparison populations in the study of rewards programs for use of lower-price providers, 2015–17

	Intervention population			Comparison population
	2015	2016	2017	2015	2016	2017
Enrollees	240,095	274,025	269,875	276,585	282,164	284,889
Employers	29	29	29	45	45	45
Average months enrolled	11.4	11.4	11.5	11.4	11.5	11.5
Average age (years)	33.5	33.4	33.6	33.1	33.0	33.1
Male (%)	47.4	47.2	47.0	50.4	50.4	50.4
Average risk score	1.06	1.03	1.03	0.97	0.98	0.99
Enrolled in HDHP (%)	28.0	27.4	27.4	26.8	28.4	30.4

SOURCE Authors’ analysis of medical claims data for 2015–17 from Health Care Service Corporation employers. NOTES Risk scores were calculated using diagnostic case groups developed by Verscend Technologies. A higher risk score is consistent with greater risk of increased spending. The intervention and comparison populations are defined in the text. HDHP is high-deductible health plan.