Table 1

Item calibrations with standard error (SE), infit statistics, and outfit statistics for the items of the Dutch WOMAC and the English WOMAC pain and physical functioning dimensions, according to the item order of the WOMAC

Calibrations are expressed in logits. Negative calibrations indicate easier items; positive calibrations indicate more difficult items.
Infit and outfit statistics >1.30 indicate items that do not contribute to the underlying construct. Statistics >1.30 are shown in italics. Infit and outfit statistics <0.70 indicate items that are muted.
1. Walking on a flat surface−0.470.131.101.11−
2. Going up or down stairs−−
3. At night while in bed0.630.13 1.31
4. Sitting or lying0.850.130.730.731.030.100.830.82
5. Standing upright0.130.130.850.83−
Physical functioning
8. Descending stairs0.
9. Ascending stairs−0.650.120.940.91−0.580.100.830.84
10. Rising from sitting0.000.120.580.57−
11. Standing0.320.
12. Bending to floor−−0.770.101.020.97
13. Walking on flat0.410.
14. Getting in/out of car−0.910.120.780.77−0.690.100.670.68
15. Going shopping−0.870.120.910.88−0.900.100.800.77
16. Putting on socks/stockings−0.820.12 1.56 1.51 −0.940.101.291.27
17. Rising from bed0.560.120.710.700.590.100.760.76
18. Taking off socks/stockings−−
19. Lying in bed1. 1.35 1.34
20. Getting in/out of bath0.−
21. Sitting1.540.121.000.961.560.090.960.98
22. Getting on/off toilet0.510.120.680.671.
23. Heavy domestic duties−1.560.130.850.87−1.720.101.111.06
24. Light domestic duties0.860.120.730.730.900.091.041.02