Average WOMAC pain item calibrations, SE, and INFIT statistic ordered by calibration
| WOMAC pain item | Number | Average item calibration (logits) | SE | INFIT statistic (MSQ) |
|---|---|---|---|---|
| Osteoarthritis | ||||
| Sitting pain | 655 | 0.39 | 0.03 | 0.88 |
| Night pain | 655 | 0.28 | 0.03 | 1.20 |
| Pain walking | 655 | 0.10 | 0.03 | 0.87 |
| Standing pain | 655 | −0.06 | 0.03 | 0.96 |
| Pain on stairs | 655 | −0.71 | 0.03 | 1.12 |
| Rheumatoid arthritis | ||||
| Sitting pain | 1013 | 0.25 | 0.02 | 0.94 |
| Night pain | 1013 | 0.11 | 0.02 | 1.16 |
| Pain walking | 1013 | 0.02 | 0.02 | 1.05 |
| Standing pain | 1013 | 0.02 | 0.02 | 0.83 |
| Pain on stairs | 1013 | −0.40 | 0.02 | 1.10 |
| Fibromyalgia | ||||
| Pain walking | 537 | 0.32 | 0.03 | 0.78 |
| Sitting pain | 537 | 0.08 | 0.03 | 0.95 |
| Night pain | 537 | 0.07 | 0.03 | 1.30 |
| Standing pain | 537 | 0.00 | 0.03 | 0.82 |
| Pain on stairs | 537 | −0.47 | 0.03 | 1.24 |
Negative calibrations indicate more difficult items. The more positive the score the easier the item. INFIT statistics >1.2–1.3 indicate that the item does not contribute to the underlying construct. INFIT (MNSQ) values of <0.7–0.8 indicate items that are muted.