Table 3 Estimation results of the three-period difference-in-differences analysis
Dependent Variable | Dialysis cost | Total medical claims costs (excluding dialysis costs) | ||
|---|---|---|---|---|
Estimation method | Random Effect | Fixed Effect | Fixed Effect (robust) | Fixed Effect (robust) |
Estamated coefficient [z-statistics] | Estimated coefficient [t -statistics] | Estimated coefficient [t -statistics] | Estimated coefficient [t -statistics] | |
T: treatment group dummy variable (β1) | −0.0098 [− 0.50] | − 0.0086 [− 0.44] | −0.0080 [−1.77] | 0.0432 [1.31] |
A: after-intervention dummy variable (β2) | 0.0160 [3.00]** | 0.0161 [3.02]** | 0.0160 [1.63] | 0.0383 [3.87]** |
TA: treatment group and after-intervention dummy variable (β3) | −0.0310 [−1.25] | − 0.0300 [− 1.21] | −0.0299 [−2.13]* | −0.0886 {−2.49]* |
TB: treatment group and before-intervention dummy variable (β4) | 0.0397 [1.82] | 0.0411 [1.88] | 0.0410 [2.72]** | −0.0158 [− 0.47] |
B: before-intervention dummy variable (β5) | −0.0474 [−8.02]** | −0.0475 [− 8.04]** | −0.0475 [−3.31]** | −0.0477 [− 4.63]** |
Female sex dummy variable | − 0.0274 [− 0.36] | Omitted | Omitted | Omitted |
Age | −0.0449 [− 9.56]** | Omitted | Omitted | Omitted |
Charlson comorbidity index score | 0.0049 [3.66]** | 0.0043 [3.24]** | 0.0040 [1.16] | 0.0812 [20.37]** |
Ondo dummy variable | −0.0894 [− 0.089] | Omitted | Omitted | Omitted |
Kamagari dummy variable | 0.1206 [0.91] | Omitted | Omitted | Omitted |
Primary income earner dummy variable | −0.0584 [− 0.75] | Omitted | Omitted | Omitted |
Secondary income earner dummy variable | 0.6652 [6.30]** | Omitted | Omitted | Omitted |
Constant | 3.1846 [9.75]** | 0.2479 [65.88]** | 0.2479 [28.49]** | 8.1396 [882.56]** |
Diagnostic Test | ||||
Number of observations | 80,297 | 80,297 | 80,297 | 80,297 |
Number of individuals | 2856 | 2856 | 2856 | 2856 |
R2 within | 0.0012 | 0.0012 | 0.0012 | 0.0253 |
between | 0.0387 | 0.0044 | 0.0044 | 0.0851 |
overall | 0.0424 | 0.0014 | 0.0014 | 0.0512 |
sigma_u | 1.6007 | 1.6457 | 1.6457 | 0.7619 |
sigma_e | 0.5236 | 0.5235 | 0.5235 | 0.7176 |
rho | 0.9033 | 0.9080 | 0.9080 | 0.5298 |