Table 3.

Differential Changes in Performance 3 Years Post-Transaction for Acquired Hospitals as Compared with Control Hospitals.^*

Performance Measure	No. of Hospital-Yr	Mean in Control Hospitals†	Pretransaction Difference between Acquired and Control Hospitals (95% CI)‡	Differential Change from Pretransaction Period to Third Post-Transaction Year (95% CI)	P Value§
			standard deviations
Patient-experience composite	24,435	—	−0.12 (−0.24 to −0.01)	−0.17 (−0.26 to −0.07)¶	0.002
Clinical-process composite	18,734	—	−0.17 (−0.32 to −0.02)	0.22 (0.05 to 0.38)	0.03
		percent	percentage points
Rate of death within 30 days after admission	25,999	6.49±1.31	−0.17 (−0.36 to 0.03)	0.03 (−0.20 to 0.14)	0.72
Rate of readmission within 30 days after discharge	25,999	16.56±2.41	−0.23 (−0.63 to 0.16)	−0.10 (−0.53 to 0.34)	0.72

^*Plus-minus values are means ±SD. Hospital-level observations were weighted according to count of hospital beds measured in the year before the transaction for acquired hospitals and in 2011 for control hospitals. Pretransaction differences and differential changes were adjusted for patient characteristics and hospital, year, state-by-year, and hospital-characteristic-by-year fixed effects.

^†Means in control hospitals were calculated in 2011. Means for z scores across all hospitals are equal to zero by design; thus, mean z scores for control hospitals are close to zero, not informative, and not reported. See Tables S2 and S3 for 2008 means of raw scores for each item.

^‡Negative values for pretransaction differences between acquired hospitals and control hospitals indicate that acquired hospitals had lower performance than control hospitals in the pretransaction period.

^§P values have been adjusted for multiple comparisons. See Table S10 for details.

^¶A 0.17-SD decrease in the patient-experience measure is analogous to a fall from the 50th to the 41st percentile in the performance distribution of control hospitals.