Table 3.
Summary Statistics for Model Covariates
| 2000 | ||||
|---|---|---|---|---|
| Variable | Mean | SD | Minimum | Maximum |
| MSA commercial HMO HHI (=1 if monopoly, excludes Medicare and Medicaid)* | 0.33 | 0.14 | 0.12 | 1.00 |
| MSA number of HMOs* | 11.15 | 4.64 | 1.0 | 23.41 |
| MSA HMO penetration* | 0.34 | 0.12 | 0.01 | 0.70 |
| MSA hospital HHI* (=1 if monopoly) | 0.25 | 0.14 | 0.05 | 0.85 |
| For-profit health plan | 0.75 | 0.43 | 0.00 | 1.00 |
| Staff/group model plan (mixed model) | 0.03 | 0.18 | 0.00 | 1.00 |
| IPA/network model plan (mixed model) | 0.64 | 0.48 | 0.00 | 1.00 |
| Plan age (years) | 15.23 | 8.75 | 0.30 | 57.00 |
| Publicly reports HEDIS/CAHPS | 0.72 | 0.45 | 0.00 | 1.00 |
| Blue Cross Blue Shield affiliation*,† | 0.16 | 0.36 | 0.00 | 1.00 |
| Percentage of employees in MSA in large firms*,† | 0.51 | 0.04 | 0.36 | 0.60 |
| Percentage of federal employees in MSA*,† | 0.02 | 0.02 | 0.01 | 0.16 |
| Percentage of MSA population under age 5*,† | 0.04 | 0.02 | 0.01 | 0.08 |
| Percentage of MSA population age 65 and older*,† | 0.06 | 0.03 | 0.01 | 0.15 |
| MSA per capita income (thousands)*,† | 28.02 | 4.22 | 12.76 | 51.87 |
| Percentage of MSA population nonwhite*,† | 0.18 | 0.10 | 0.01 | 0.68 |
| β-blocker medication after heart attack—hybrid data collection | 0.76 | 0.42 | 0.00 | 1.00 |
| Comprehensive diabetes care—annual eye exam rate—hybrid data collection | 0.96 | 0.20 | 0.00 | 1.00 |
| Comprehensive diabetes care—hemoglobin A1c screening rate—hybrid data collection | 0.96 | 0.20 | 0.00 | 1.00 |
| Comprehensive diabetes care—lipid screening rate—hybrid data collection | 0.96 | 0.20 | 0.00 | 1.00 |
| Comprehensive diabetes care—nephropathy monitoring rate—hybrid data collection | 0.96 | 0.20 | 0.00 | 1.00 |
| LDL cholesterol screening rate—hybrid data collection | 0.81 | 0.39 | 0.00 | 1.00 |
*
Variables weighted for plans serving multiple MSAs.
†
Variables included only in the cross-sectional models due to collinearity with the fixed effect (models 1 and 2 reported in the Appendix).
CAHPS, Consumer Assessment of Health Plans Survey; HEDIS, Healthcare Effectiveness Data and Information Set; HHI, Herfindahl–Hirschman Index; HMO, health maintenance organization; β-blocker, Betablocker; LDL, low-density lipoprotein; MSA, Metropolitan Statistical Area; SD, standard deviation.