| IRT item parameters | ||||
---|---|---|---|---|---|
 | Discrim | Difficulty: location parameters | |||
I_irt item | a | b1 (se) | b2 (se) | b3 (se) | b4 (se) |
I1. Does remaining standing for 30 minutes increase your pain? | 1.38 | -4.25 (0.73) | -2.39 (0.29) | -1.22 (0.16) | -0.07 (0.11) |
I2. What degree of difficulty do you have bending and rotating your affected joint? | 1.46 | -3.55 (0.47) | -2.31 (0.25) | -0.68 (0.12) | 1.08 (0.14) |
I3. How would you describe the pain you usually have from your joint? | 2.33 | -5.34 (-) | -2.47 (0.35) | -0.81 (0.09) | 1.56 (0.13) |
I4. How often have you had severe pain from your arthritis? | 2.15 | -2.82 (0.30) | -1.67 (0.15) | -0.56 (0.09) | 1.21 (0.11) |
I5. How active has your arthritis been? | 2.50 | -2.81 (0.31) | -1.94 (0.17) | -0.50 (0.08) | 1.25 (0.11) |
I6. Have you been troubled by pain from your joint in bed at night? | 1.52 | -2.65 (0.30) | -1.22 (0.15) | -0.45 (0.11) | 0.75 (0.12) |
I7. How severe is your stiffness after first wakening in the morning? | 1.81 | -2.88 (0.31) | -1.54 (0.15) | 0.11 (0.09) | 2.02 (0.19) |
I8. How severe is your stiffness after sitting, lying or resting later in the day? | 1.51 | -3.62 (0.52) | -1.64 (0.19) | 0.54 (0.11) | 2.54 (0.27) |
I9. How long has your morning stiffness usually lasted from the time you wake up? | 1.34 | -3.38 (0.43) | -1.05 (0.16) | 0.65 (0.12) | 1.57 (0.19) |
I11. Have you felt that your knee or hip might suddenly 'give way' or let you down? | 1.32 | -2.62 (0.32) | -0.79 (0.14) | 0.97 (0.14) | 2.24 (0.25) |
I12. How often have you had pain in two or more joints at the same time? | 1.09 | -2.43 (0.32) | -0.63 (0.15) | 0.76 (0.15) | 2.52 (0.31) |
I13. Have you had any sudden, severe pain – 'shooting', 'stabbing' or 'spasms' – from the affected joint? | 1.33 | -2.98 (0.38) | -0.83 (0.14) | 1.34 (0.17) | 2.72 (0.31) |
TOTAL | Â | Â | Â | Â | Â |