Table 1.
Characteristics of the Sample Population, Johns Hopkins Overuse Index, and Structural Factors, by Hospital Referral Region
| Variable | Mean | Std. Dev. | Min | Max |
|---|---|---|---|---|
| Johns Hopkins Overuse Index | 0 | 1.00 | − 2.07 | 4.35 |
| Population characteristics | ||||
| Medicare beneficiaries | 83,854 | 77,063 | 14,410 | 468,802 |
| ACG® (case-mix measure) | 0.98 | 0.09 | 0.73 | 1.28 |
| Age (years) | 77 | 0.8 | 75 | 79 |
| Gender (%) | ||||
| Female (%) | 62 | 2.1 | 56 | 68 |
| Race (%) | ||||
| White | 90.0 | 9.6 | 28 | 99 |
| African Americans | 6.3 | 7.4 | 0 | 34 |
| Asian | 1.1 | 3.1 | 0 | 36 |
| Hispanic | 1.3 | 3.1 | 0 | 26 |
| Native Americans | 0.5 | 1.4 | 0 | 15 |
| Other | 0.1 | 2.3 | 0 | 35 |
| Medicaid eligible population (%) | 14 | 6.8 | 1.8 | 50 |
| Health care capacity* | ||||
| Hospital beds | 2.51 | 0.62 | 1.44 | 4.71 |
| Primary care physicians | 0.70 | 0.12 | 0.44 | 1.17 |
| Medical specialists | 0.41 | 0.09 | 0.23 | 0.80 |
| Hospital-based specialists | 0.24 | 0.03 | 0.16 | 0.31 |
| Surgeons | 0.41 | 0.06 | 0.24 | 0.70 |
*The number of hospital beds or clinicians per 1000 residents. ACG®, Adjusted Clinical Group. “Hospital-based specialists” includes anesthesiologists, pathologists, and radiologists