APPENDIX EXHIBIT A2.

Trend Breaks in Measures of Consolidation and Prices, Pre- to Post-Period

	(1)	(2)	(3)	(4)	(5)	(6)
VARIABLES	Physician-Hospital Integration	Physician HHI	Weighted Average TIN Size	Hospital HHI	Inpatient Price Index	Outpatient Price Index
Year	0.011***	9.596	2.513**	51.860***	0.049***	0.023***
	(0.001)	(6.343)	(1.236)	(12.018)	(0.002)	(0.001)
Year*Post	0.002**	5.418	1.559*	1.428	−0.006***	0.000
	(0.001)	(3.828)	(0.935)	(6.539)	(0.001)	(0.001)
Observations	1,734	1,734	1,734	1,734	1,356	1,356
R-squared	0.948	0.976	0.941	0.981	0.927	0.976
MSA FE	Yes	Yes	Yes	Yes	Yes	Yes
F Statistic	56.62	6.377	11.31	17.88	508.2	292.2

Robust standard errors in parentheses

^***p<0.01,

^**p<0.05,

^*p<0.1

SOURCE Authors’ analysis of data from the Centers for Medicare and Medicaid and Irving Levin Associates.

NOTES All columns present results from separate between-market analyses, clustering standard errors at the MSA level. Physician’s average group size is calculated as the average count of physician billing for outpatient care within a TIN, weighting each TIN by its share of total physicians in the MSA. MSA is Metropolitan Statistical Area. TIN is Tax Identification Number. HHI is Herfindahl Hirschman Index.