Table 2.
Results for the random-effects Tobit model for composite time trade-off (cTTO) data and for the hybrid model based on cTTO plus discrete choice experiment (DCE) data. Beta coefficients should be read as utility decrements in the calculation of health-related quality of life
| Dimension level | Random-effects Tobit model | Heteroscedastic censored hybrid model | ||||||
|---|---|---|---|---|---|---|---|---|
| β | [95 % CI] | β | P value | β | SE | [95 % CI] | ||
| Regular dummies | Regular dummies | Incremental dummies | Incremental dummies | Regular dummiesa | Regular dummies | Regular dummies | ||
| mo2 | 0.080 | [0.0499–0.1095] | 0.041 | 0.000 | 0.041 | 0.007 | [0.0265–0.0553] | |
| mo3 | 0.061 | [0.0294–0.0921] | 0.013 | 0.281 | 0.054 | 0.012 | [0.0311–0.0765] | |
| mo4 | 0.166 | [0.1315–0.2000] | 0.103 | 0.000 | 0.157 | 0.011 | [0.1347–0.1788] | |
| mo5 | 0.205 | [0.1740–0.2368] | 0.063 | 0.000 | 0.220 | 0.011 | [0.1986–0.2415] | |
| sc2 | 0.030 | [–0.0001–0.0591] | 0.035 | 0.000 | 0.035 | 0.007 | [0.0216–0.0479] | |
| sc3 | 0.045 | [0.0113–0.0783] | 0.015 | 0.179 | 0.050 | 0.011 | [0.0288–0.0704] | |
| sc4 | 0.111 | [0.0776–0.1448] | 0.094 | 0.000 | 0.144 | 0.011 | [0.1215–0.1656] | |
| sc5 | 0.172 | [0.1415–0.2020] | 0.065 | 0.000 | 0.209 | 0.010 | [0.1886–0.2291] | |
| ua2 | 0.045 | [0.0148–0.0762] | 0.033 | 0.000 | 0.033 | 0.007 | [0.0194–0.0471] | |
| ua3 | 0.085 | [0.0516–0.1179] | 0.007 | 0.531 | 0.040 | 0.011 | [0.0195–0.0608] | |
| ua4 | 0.153 | [0.1204–0.1860] | 0.099 | 0.000 | 0.139 | 0.010 | [0.1187–0.1592] | |
| ua5 | 0.172 | [0.1410–0.2021] | 0.035 | 0.007 | 0.174 | 0.011 | [0.1526–0.1951] | |
| pd2 | 0.038 | [0.0106–0.0661] | 0.048 | 0.000 | 0.048 | 0.006 | [0.0361–0.0606] | |
| pd3 | 0.077 | [0.0430–0.1106] | 0.045 | 0.000 | 0.094 | 0.011 | [0.0718–0.1154] | |
| pd4 | 0.363 | [0.3330–0.3934] | 0.287 | 0.000 | 0.381 | 0.012 | [0.3576–0.4044] | |
| pd5 | 0.527 | [0.4947–0.5597] | 0.156 | 0.000 | 0.537 | 0.013 | [0.5109–0.5635] | |
| ad2 | 0.084 | [0.0520–0.1158] | 0.072 | 0.000 | 0.072 | 0.007 | [0.0589–0.0851] | |
| ad3 | 0.209 | [0.1727–0.2449] | 0.119 | 0.000 | 0.191 | 0.011 | [0.1699–0.2121] | |
| ad4 | 0.430 | [0.3969–0.4630] | 0.239 | 0.000 | 0.430 | 0.011 | [0.4081–0.4512] | |
| ad5 | 0.566 | [0.5359–0.5970] | 0.188 | 0.000 | 0.618 | 0.013 | [0.5935–0.6428] | |
| Constant | − 0.004 | [– 0.0451 to 0.0364] | Not used | Not used | ||||
ad anxiety/depression, CI confidence interval, mo mobility, pd pain/discomfort, sc self-care, SE standard error, ua usual activity
aPreferred model