TABLE 7.

Effect of MA managed care penetration on HEDIS quality measures, readmissions, and mortality

	Diabetes hemoglobin	Diabetes retinal	Diabetes LDL	LDL post-cardiac event
Penetration (instrumented)	−0.229a   (0.0792)	0.307a   (0.112)	0.0614   (0.0970)	−0.159c   (0.0814)
Observations	5,213,774	5,213,774	5,213,774	2,754,546
R2	0.034	0.031	0.037	0.064
Mean of dep. var.	82	57	82	79
10 pct. pt. pen. incr. effect (%)	−2.793	5.386	0.749	−2.013

	Breast cancer screening	HEDIS composite	Readmissions	Mortality
Penetration (instrumented)	0.103 (0.0835)	−0.0487   (0.0563)	−0.251   (0.168)	0.0112   (0.00748)
Observations	3,645,522	9,786,818	60,940,793	60,940,793
R2	0.022	0.034	0.040	0.116
Mean of dep. var.	64	71	61	6.8
10 pct. pt. pen. incr. effect (%)	1.609	−0.686	−4.115	1.647

Data sources: CMS Medicare claims data inpatient files, Medicare beneficiary enrollment files, and MA Ratebook Files for 1999–2011.

Notes: MA Penetration, HEDIS composite, and mortality are percentages (ranging from 0 to 100). Readmissions are per 1,000 enrollees. Regressions include county and year fixed effects; enrollee-level covariates; and county-level demographics, economic conditions, and health-care workforce. Standard errors in parentheses (robust, clustered on county).

^ap < 0.01,

^bp < 0.05,

^cp < 0.10.