Table 3.

SHR and AHR Rates and ERR Changes by Hospital Characteristics

Characteristic	Mean Readmission Rate, %						No. of Hospitals Whose ERR Changed From SHR to AHRb
	Unadjusted			Adjusted
	SHR	AHR	Underestimation, %a	SHR	AHR	Underestimation, %a	ERR >1 to ≤1c	ERR ≤1 to >1d	Total
Overall	2.38	3.10	23.18	2.72	3.59	24.22	10	10	20
Children’s hospital status
Children’s	5.30	5.84	9.16	4.36	4.83	9.68	0	0	0
Nonchildren’s	2.17	2.90	25.23	2.60	3.50	25.67	10	10	20
Teaching status
Teaching	3.67	4.23	13.22	3.56	4.15	14.20	2	0	2
Nonteaching	2.04	2.80	27.16	2.50	3.44	27.41	8	10	18
Annual pediatric volume, quartilee
1 (1 to <385)	2.02	2.84	28.92	2.24	3.22	30.49	2	2	4
2 (385 to <1179)	1.93	2.57	24.71	2.52	3.37	25.06	3	3	6
3 (1179 to <3947)	1.86	2.64	29.50	2.39	3.37	28.87	3	4	7
4 (3947 to 44 685)	3.67	4.31	14.78	3.69	4.38	15.56	2	1	3
Hospital location
Urban	2.20	2.88	23.57	2.74	3.62	24.50	5	6	11
Large rural city or town	2.20	2.76	20.27	2.79	3.53	20.96	4	2	6
Small and isolated small rural   town	3.25	4.29	24.10	2.59	3.50	26.04	1	2	3

Abbreviations: AHR, all-hospital readmission; ERR, excess readmission ratio; SHR, same-hospital readmission.

^aCalculated as the relative percentage that SHRs underestimate AHRs using the formula |(AHR − SHR)/AHR|.

^bRepresent predicted divided by expected readmissions. Hospitals with an ERR greater than 1 incur penalties. Predicted readmissions are calculated by estimating the probability of readmission for each patient at a hospital and adding the probabilities for all of the hospital’s patients. Expected readmissions are calculated by estimating the probability of readmission for each of a hospital’s patients if admitted to an average hospital and then adding the probabilities for all of the hospital’s patients.

^cIndicates hospitals whose anticipated performance improved (and who would therefore no longer be subject to penalties under a program with the penalty criteria used in Medicare’s Hospital Readmissions Reduction Program) if AHR rates were used in ERR calculations.

^dIndicates hospitals whose anticipated performance worsened (and who would become subject to penalties) if AHR rates were used in ERR calculations.

^eGiven as number of pediatric admissions.