Table 4.
Discriminative validity
| Mean | SD | Obs | SES | |
|---|---|---|---|---|
| EQ-5D vs FSS groups | ||||
| Mild/no fatigue | 0.775 | 0.218 | 297 | 0.615 |
| Moderate fatigue | 0.641 | 0.233 | 369 | 0.803 |
| Severe fatigue | 0.454 | 0.3 | 357 | |
| FFS total | 0.614 | 0.285 | 1023 | |
| F-statistic | 131.84 | Prob < | 0.0001 | |
| Bartlett’s chi2 | 40.065 | Prob < | 0.0001 | |
| SF-6D vs FSS groups | ||||
| Mild/no fatigue | 0.747 | 0.124 | 189 | 0.871 |
| Moderate fatigue | 0.639 | 0.099 | 225 | 0.879 |
| Severe fatigue | 0.552 | 0.083 | 193 | |
| FFS total | 0.645 | 0.129 | 607 | |
| F-statistic | 172.46 | Prob < | 0.0001 | |
| Bartlett’s chi2 | 30.047 | Prob < | 0.0001 | |
| MSIS-8D vs FSS groups | ||||
| Mild/no fatigue | 0.764 | 0.115 | 202 | 0.739 |
| Moderate fatigue | 0.679 | 0.134 | 240 | 1.381 |
| Severe fatigue | 0.494 | 0.186 | 208 | |
| FFS total | 0.646 | 0.184 | 650 | |
| F-statistic | 180.71 | Prob < | 0.0001 | |
| Bartlett chi2 | 51.434 | Prob < | 0.0001 | |
SD standard deviation, obs observations, SES standardised effect size, FSS Fatigue Severity Scale, EQ-5D EuroQoL EQ-5D-3L, SF-6D Short-Form 6D, MSIS-8D Multiple Sclerosis Impact Scale – Eight Dimensions