Table 1.
Item locations and fit statistics for the 15 items of the FPDI function and pain subscales
| Location (SE) (logits) | Item fit residual | Chi-square probability | F-test probability | |
| Functioning Subscale | ||||
| 1. Avoid walking outside | 2.166 (0.223) | -0.141 | 0.5146 | 0.6898 |
| 2. Avoid walking long distances | -0.963 (0.160) | -0.989 | 0.3109 | 0.1625 |
| 3. Don't walk in a normal way | -0.082 (0.169) | 0.984 | 0.2666 | 0.4895 |
| 4. Walk slowly | -0.867 (0.164) | -1.050 | 0.7594 | 0.4466 |
| 5. Have to stop and rest feet | 0.115 (0.175) | -0.941 | 0.3065 | 0.2227 |
| 6. Avoid hard or rough surfaces | -1.339 (0.156) | -0.374 | 0.6770 | 0.5616 |
| 7. Avoid standing for a long time | -1.058 (0.165) | -1.011 | 0.5779 | 0.4415 |
| 8. Catch the bus or use the car more often | -0.897 (0.153) | 0.809 | 0.2563 | 0.3129 |
| 9. Need help with housework or shopping | 1.760 (0.208) | -1.757 | 0.1866 | 0.0210 |
| 11. Get irritable when feet hurt | 1.165 (0.191) | 2.302 | 0.0416 | 0.0737 |
| Pain Subscale | ||||
| 10. Do everything with more pain or discomfort | -0.868 (0.148) | 1.682 | 0.2000 | 0.2046 |
| 14. Constant pain in feet | -0.184 (0.147) | -1.207 | 0.0275 | 0.0030* |
| 15. Feet are worse in the morning | 0.513 (0.150) | 0.318 | 0.1979 | 0.2203 |
| 16. Feet more painful in the evening | -0.201 (0.151) | -0.478 | 0.2735 | 0.1327 |
| 17. Get shooting pains in feet | 0.739 (0.154) | 1.237 | 0.5830 | 0.6318 |
* Significant misfit after Bonferroni correction