APPENDIX EXHIBIT A5.
Association Between MSA-level 2014 ACO Penetration and Provider Market Structure
| (1) | (2) | (3) | (4) | (5) | (6) | |
|---|---|---|---|---|---|---|
| VARIABLES | Physician-Hospital Integration | Physician HHI | Weighted Average TIN Size | Hospital HHI | Inpatient Price Index | Outpatient Price Index |
| Post | 0.04*** | 28.75 | 6.44 | 154.24*** | 0.11*** | 0.06*** |
| (0.01) | (24.18) | (6.23) | (35.93) | (0.01) | (0.01) | |
| Post*ACOpenetration2014 | −0.02 | 130.68 | 27.02 | −143.73 | −0.04 | 0.03 |
| (0.02) | (72.53) | (17.68) | (125.43) | (0.02) | (0.01) | |
| Insurance HHI | −0.00 | 0.02 | −0.00 | −0.06 | 0.00 | 0.00 |
| (0.00) | (0.02) | (0.00) | (0.04) | (0.00) | (0.00) | |
| MA HMO Share | −0.11 | 155.24 | 38.00 | 584.89 | 0.50* | −0.01 |
| (0.08) | (273.28) | (59.46) | (1,118.46) | (0.20) | (0.09) | |
| Commercial HMO Share | −0.09* | −37.08 | −42.44 | −643.11* | −0.26*** | −0.14* |
| (0.04) | (214.58) | (34.03) | (323.17) | (0.07) | (0.05) | |
| Observations | 1,734 | 1,734 | 1,734 | 1,734 | 1,356 | 1,356 |
| R-squared | 0.95 | 0.98 | 0.94 | 0.98 | 0.88 | 0.97 |
| MSA FE | Yes | Yes | Yes | Yes | Yes | Yes |
| F Statistic | 21.31 | 4.251 | 5.676 | 7.069 | 128.6 | 129.0 |
Robust standard errors in parentheses
***
p<0.001,
**
p<0.01,
*
p<0.05
SOURCE Authors’ analysis of data from the Centers for Medicare and Medicaid and Irving Levin Associates.
NOTES All columns are the results of separate between-market analyses, clustering standard errors at the MSA level. Physician’s average group size is calculated as the average count of physicians billing for outpatient care within a TIN, weighting each TIN by its share of total physicians in the MSA. MSA is Metropolitan Statistical Areas. ACO is Accountable Care Organization. HMO is Health Maintenance Organization. HHI is Herfindahl Hirschman Index.