Table 1.
Descriptive Statistics on Medical Groups and IPAs: Compensation Methods, HMO Market Penetration, and Organizational Characteristics
| Medical Groups | IPAs | |
|---|---|---|
| Primary care payment based on productivity (%) | 51.8 (42.4) | 41.6 (43.0) |
| Specialist payment based on productivity (%) | 51.0 (43.1) | 71.2 (36.6) |
| HMO market penetration, 0–20% | 0.26 (0.44) | 0.18 (0.38) |
| HMO market penetration, 21–30% | 0.24 (0.43) | 0.27 (0.45) |
| HMO market penetration, 31–45% | 0.29 (0.45) | 0.24 (0.43) |
| HMO market penetration, more than 45% | 0.22 (0.41) | 0.32 (0.47) |
| Number of physicians | 128.8 (289.3) | 406.2 (521.3) |
| Multispecialty physician membership | 0.70 (0.21) | 0.88 (0.11) |
| Owned by hospital or HMO | 0.44 (0.50) | 0.18 (0.39) |
| Age of organization (years) | 22.3 (22.7) | 8.26 (6.11) |
| N | 423 | 215 |
Note: Standard deviations in parentheses.