Table 4.

Measures of concentration for different product market definitions based on hospital system (mean)

	HHI	MS	CR3	NC	NZIP	Distance 1)	# of HS
Total	0.19	0.27	0.59	14.19	35.27	20.38	910
Standard procedures
Nonsurgical procedures
PNEU	0.34	0.46	0.74	8.41	23.53	12.23	759
STROKE	0.30	0.38	0.71	8.47	24.84	16.78	762
BIRTH	0.31	0.45	0.76	5.92	26.36	12.92	579
Surgical procedures
APP	0.33	0.47	0.72	8.73	23.75	15.19	679
CHOL	0.34	0.48	0.75	8.02	24.73	12.02	687
Orthopaedic surgical procedures
HAP	0.19	0.30	0.59	13.60	38.12	25.58	654
KAP	0.19	0.31	0.59	13.09	38.69	23.80	617
HIP	0.42	0.55	0.80	6.29	21.39	11.22	680
ORTHO	0.20	0.32	0.61	12.10	36.91	21.10	728
Complex surgical procedures
AAA	0.44	0.60	0.85	6.11	21.97	26.51	305
CABG	0.56	0.70	0.92	1.58	61.96	50.97	62

Notes: ¹⁾Data was censored at the 99th percentile to eliminate extreme outliers. PNEU - pneumonia; APP - appendectomy; CHOL - cholecystectomy; HAP - hip arthroplasty; KAP - knee arthroplasty; HIP - hip fracture; ORTHO - joint category for HAP, KAP and HIP; AAA - intact abdominal aortic aneurysm; CABG - coronary artery bypass surgery.