Table 2.
Main estimates and sensitivity analyses (market-level model).*
| Variables | (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) |
|---|---|---|---|---|---|---|---|---|---|
| Base IV | No county risk | No plan risk | Linear year | Unweighted | Large markets | Interaction | HHI | HHI* bench | |
| Benchmark | 0.534*** (0.0556) | 0.549*** (0.0566) | 0.542*** (0.0547) | 0.519*** (0.0535) | 0.521*** (0.0707) | 0.544*** (0.0555) | 0.699*** (0.164) | 0.515*** (0.0541) | 0.571*** (0.0772) |
| Risk (FFS) | −79.79** (32.24) | −75.10** (31.94) | −97.62*** (32.23) | −89.27** (36.56) | −74.40*** (28.19) | −80.64** (32.70) | −72.93** (29.90) | −70.53** (28.20) | |
| Risk (Plan) | 26.13 (19.01) | 19.55 (20.37) | 20.25 (19.78) | 21.46 (19.44) | 28.54 (22.24) | 22.78 (19.37) | 24.52 (18.83) | 26.19 (17.64) | |
| FFS cost | 0.0686* (0.0383) | −0.0149 (0.0155) | 0.0659* (0.0378) | 0.0654* (0.0372) | 0.112** (0.0467) | 0.0584 (0.0363) | 0.0702* (0.0396) | 0.0639* (0.0356) | 0.0606* (0.0330) |
| Pop (1000s) | 0.00743 (0.0121) | 0.00587 (0.0130) | 0.00703 (0.0120) | 0.0272** (0.0120) | 0.0441 (0.0298) | 0.00403 (0.0127) | 0.0119 (0.0118) | −0.00581 (0.0129) | −0.00937 (0.0134) |
| Insurers | −1.138*** (0.145) | −0.993*** (0.121) | −1.080*** (0.157) | −1.489*** (0.139) | −1.642*** (0.272) | −1.082*** (0.139) | 4.370 (4.060) | −0.983*** (0.160) | −1.039*** (0.185) |
| Insurers* Bench | −0.00634 (0.00471) | ||||||||
| HHI (beds) | −0.00699*** (0.00271) | 0.0237 (0.0248) | |||||||
| HHI* Bench | −3.56e-05 (2.88e-05) | ||||||||
| Market FE | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| Year FE | Y | Y | Y | Y | Y | Y | Y | Y | |
| Year (linear) | 6.597*** (1.283) | ||||||||
| Observations | 7,299 | 7,299 | 7,299 | 7,299 | 7,299 | 5,135 | 7,299 | 7,299 | 7,299 |
| R-squared | 0.398 | 0.391 | 0.397 | 0.366 | 0.353 | 0.408 | 0.396 | 0.406 | 0.408 |
| Markets | 1,762 | 1,762 | 1,762 | 1,762 | 1,762 | 1,229 | 1,762 | 1,762 | 1,762 |
Robust standard errors in parentheses clustered by state.
***
p<0.01,
**
p<0.05,
*
p<0.1
*
The base IV model with market fixed effects has average market bids as the dependent variable using data from 2006–2010. All covariates are at the market level. FFS costs are actual realized Medicare Part A and Part B costs among fee-for-service beneficiaries. Markets are determined using HMO plans in the Medicare Advantage program. All amounts are inflated to 2012 U.S. dollars.