Table 4.
Least Squared Estimates of (1) Using Seven Alternative Measures of Market Concentration
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | |
|---|---|---|---|---|---|---|---|
| 2002–5 Trend | −0.0024*** | −0.0024*** | −0.0022*** | −0.0026*** | −0.0026*** | −0.0023*** | −0.0028*** |
| (0.0002) | (0.0002) | (0.0002) | (0.0002) | (0.0002) | (0.0002) | (0.0002) | |
| 2006–8 Trend | −0.0018*** | −0.0016*** | −0.0020*** | −0.0012** | −0.0015** | 0.0005 | −0.0014** |
| (0.0004) | (0.0004) | (0.0004) | (0.0005) | (0.0005) | (0.0004) | (0.0005) | |
| 2002–5 Trend × nlhhi | 0.0002 | 0.0003 | 0.0000 | 0.0003* | 0.0003* | 0.0002 | 0.0006** |
| (0.0002) | (0.0002) | (0.0003) | (0.0001) | (0.0001) | (0.0002) | (0.0002) | |
| 2006–8 Trend × nlhhi | −0.0012* | −0.0015** | −0.0017* | −0.0009** | −0.0009** | −0.0009** | −0.0012** |
| (0.0005) | (0.0005) | (0.0007) | (0.0003) | (0.0003) | (0.0003) | (0.0004) | |
| nlhhi | – | −0.0026 | −0.0022 | 0.0036 | 0.0013 | 0.0099 | 0.0091 |
| (0.0032) | (0.0042) | (0.0070) | (0.0067) | (0.0061) | (0.0073) | ||
| Patient characteristics | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Hospital fixed effects | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| GP fixed effects | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| N | 422,350 | 422,350 | 382,026 | 439,365 | 437,185 | 421,094 | 461,508 |
| R2 | 0.126 | 0.126 | 0.127 | 0.126 | 0.126 | 0.126 | 0.124 |
Significant at 5% level.
Significant at 1%.
Significant at 0.1%. Column (1) nlhhi = negative ln of HHI within 95% variable market with competition measured as the average HHI between 2002 and 2005 prior to the reforms; column (2) nlhhi = negative ln of HHI within 95% variable market where competition is measured between hospital trusts, not sites; column (3) nlhhi = negative ln of HHI within 75% variable radius market; column (4) nlhhi = negative ln of HHI within fixed 30 km radius market; column (5) nlhhi = negative ln of HHI within market defined by 30-min drive time from each GP practice; column (6) nlhhi is centred on hospitals and defined within a 20 km fixed radius; column (7) nlhhi = negative log of HHI based on predicted patient flows. Dependent variable = 1 if patient died within 30-days of their admission to hospital following an emergency AMI. Hospital characteristics: hospital type (foundation trust, teaching hospital or traditional acute hospital), number of AMIs treated at the hospital per year. Patient characteristics: age, gender, Charlson comorbidity score and patient socioeconomic status measured using the income component of the 2004 Index of Multiple Deprivations at the output area.
Standard errors are clustered on GP-practices. HHI, Herfindahl-Hirschman Indexes; AMI, acute myocardial infarction.