Likelihood ratios and posterior probabilities of change related to MCID considering important change at levels 3 and 5 on the GROC scale
| ROC cut-off point (MCID) | Prior probability meaningful change (%) | Positive likelihood ratio (95% CI) | Negative likelihood ratio (95% CI) | Posterior probability of clinical change (%) if cut-off is achieved (95% CI) | Posterior probability of clinical change (%) if cut-off is not achieved (95% CI) | |
|---|---|---|---|---|---|---|
| Equating minimal important change with a GROC ≥3 | ||||||
| Absolute change score | >13 | 78.9 | 15.0 (12.8 to 17.6) | 0.22 (0.03 to 1.6) | 98 (89 to 100) | 45 (34 to 57) |
| Relative change score | >15.4 | 77.8 | 1.91 (1.2 to 3.0) | 0.09 (0.03 to 0.3) | 87 (81 to 91) | 24 (10 to 50) |
| Equating minimal important change with a GROC ≥5 | ||||||
| Absolute change score | >15 | 56.7 | 10.7 (9.2 to 12.5) | 0.2 (0.1 to 0.7) | 94 (82 to 98) | 20 (13 to 31) |
| Relative change score | >50 | 56.7 | 6.6 (5.0 to 8.8) | 0.5 (0.2 to 1.6) | 89 (73 to 96) | 40 (33 to 47) |
GROC, global rating of change; MCID, minimum clinically important difference; ROC, receiver-operating characteristic curve.