Skip to main content
. 2021 Jul 5;28(9):5166–5182. doi: 10.1245/s10434-021-09887-y

RMT item level fit statistics and differential item function results

Scales Item fit statistics Differential item function*
Item Location SE Fit residual df χ2 df Probability Dataset Age-group
Unadj Adj Unadj Adj
Symptoms
Pain touch − 1.20 0.04 − 1.29 2880 3.90 9 0.92 No No No No
Pain rest − 1.05 0.03 − 4.41 2899 6.29 9 0.71 No No No No
Temperature − 0.75 0.03 2.17 2877 3.71 9 0.93 No No No No
Stiff − 0.72 0.03 − 2.03 2859 4.17 9 0.90 Yes Yes No No
Sleeping − 0.29 0.03 − 1.05 2893 2.85 9 0.97 Yes Yes No No
Aching − 0.29 0.03 − 7.90 2875 14.69 9 0.10 Yes Yes No No
Numb − 0.27 0.03 7.08 2864 12.11 9 0.21 No No No No
Pressure − 0.16 0.03 − 6.20 2872 10.86 9 0.29 No No No No
Pain move − 0.10 0.03 − 5.44 2905 8.95 9 0.44 No No No No
Clumsy 0.07 0.03 5.07 2882 6.34 9 0.71 No No No No
Tingling 0.09 0.03 1.36 2883 3.17 9 0.96 No No No No
Tired 0.87 0.03 − 10.03 2884 18.41 9 0.03 Yes Yes Yes No
Weak 1.00 0.03 − 1.00 2893 1.61 9 1.00 No No No No
Heavy 1.14 0.03 − 6.49 2900 7.81 9 0.55 Yes Yes No No
Swelling 1.66 0.03 8.09 2912 22.31 9 0.01 Yes No Yes No
Function
Clothes − 1.07 0.04 − 3.22 2400 5.70 8 0.68 Yes Yes No No
Wash hair − 1.07 0.04 − 5.81 2383 9.93 8 0.27 No No Yes No
Buttons − 0.53 0.04 1.52 2393 1.89 8 0.98 No No Yes Yes
Hold phone − 0.47 0.04 0.42 2395 1.62 8 0.99 No No Yes No
Reach across − 0.43 0.04 − 0.83 2388 3.81 8 0.87 Yes Yes No No
Grip handle − 0.37 0.04 − 4.29 2380 7.32 8 0.50 No No No No
Hold book − 0.04 0.04 − 2.28 2373 3.22 8 0.92 Yes Yes No No
Use hands − 0.04 0.04 0.35 2383 2.79 8 0.95 No No No No
Reach overhead 0.52 0.03 5.99 2401 7.64 8 0.47 Yes Yes No No
Hold groceries 0.96 0.03 1.58 2395 1.83 8 0.99 Yes Yes No No
Do chores 1.04 0.03 − 3.04 2399 7.45 8 0.49 Yes Yes No No
Move arm 1.50 0.03 − 3.26 2383 4.31 8 0.83 No No No No
Appearance
People seeing − 0.98 0.04 1.14 2412 8.50 9 0.49 Yes Yes No No
Long-sleeved shirt − 0.90 0.04 3.66 2418 6.68 9 0.67 Yes Yes No No
Dress to hide − 0.64 0.04 1.94 2411 2.90 9 0.97 No No No No
Photos − 0.37 0.04 − 3.64 2399 5.23 9 0.81 Yes Yes No No
Noticeable − 0.16 0.04 − 5.85 2421 6.64 9 0.67 No No Yes −
Size 0.33 0.04 − 1.95 2430 3.92 9 0.92 Yes Yes No No
Certain clothes 0.42 0.03 − 2.42 2424 3.99 9 0.91 No No No No
Clothes fit 0.49 0.04 − 0.04 2416 4.50 9 0.88 No No Yes Yes
Symmetry 0.57 0.04 − 4.85 2418 9.19 9 0.42 No No No No
Sleeveless shirt 1.23 0.04 − 4.24 2426 10.57 9 0.31 No No No No
Psychological
Desperate − 1.38 0.06 − 7.41 2264 15.81 8 0.05 Yes No No No
Hopeless − 0.85 0.05 − 6.13 2271. 13.11 8 0.11 Yes No No No
Angry − 0.52 0.04 − 4.63 2280 7.70 8 0.46 Yes No No No
Depressed − 0.39 0.04 − 4.85 2275 8.33 8 0.40 No No Yes No
Stressed − 0.16 0.04 − 5.71 2267 10.94 8 0.21 Yes Yes No No
Afraid − 0.08 0.04 − 2.66 2271 3.79 8 0.88 Yes Yes Yes No
Anxious − 0.03 0.04 − 0.98 2275 2.67 8 0.95 No No Yes No
Fed-up − 0.01 0.04 − 5.17 2277 8.19 8 0.42 No No No No
Unattractive 0.66 0.04 4.86 2270 8.08 8 0.43 Yes Yes No No
Worried 0.85 0.04 1.54 2276 2.53 8 0.96 Yes No No No
Irritated 0.88 0.04 4.67 2277 7.49 8 0.48 Yes Yes No No
Frustrated 1.03 0.04 − 0.18 2276 10.64 8 0.22 Yes Yes Yes No
Information
What it is − 0.99 0.04 2.18 1325 12.47 8 0.13 No No No No
Care for it − 0.85 0.04 − 3.56 1318 10.64 8. 0.22 Yes Yes Yes No
Avoid infections − 0.40 0.04 3.31 1321 3.86 8 0.87 No No No No
How its treated 0.07 0.04 − 4.87 1320 12.96 8 0.11 No No No No
How to monitor 0.08 0.04 − 2.04 1319 6.21 8 0.62 No No No No
Possibility 0.17 0.04 5.69 1322. 12.04 8 0.15 No No Yes Yes
Healthcare team 0.51 0.04 0.22 1318 3.26 8 0.92 No No No No
How it feels 0.60 0.04 − 3.12 1319 9.91 8 0.27 No No No No
Impact on life 0.82 0.04 − 2.89 1321 12.54 8 0.13 No No No No
Sleeve
Fits − 0.45 0.03 − 4.81 1935 8.68 9 0.47 No No No No
Swelling − 0.31 0.03 2.92 1950 3.28 9 0.95 Yes Yes No No
Looks − 0.26 0.03 1.08 1946. 4.01 9 0.91 Yes Yes No No
Skin − 0.17 0.03 4.01 1945 4.82 9 0.85 No No No No
Put on − 0.14 0.03 4.35 1953 3.75 9 0.93 No No Yes No
Active 0.01 0.03 − 0.48 1942 4.66 9 0.86 Yes Yes No No
Long wear 0.12 0.03 − 3.91 1938 9.01 9 0.44 Yes Yes No No
Comfortable 0.15 0.03 − 4.66 1959 12.26 9 0.20 No No No No
Dressed 0.38 0.03 − 1.45 1941 4.94 9. 0.84 No No No No
Clothes fit 0.69 0.03 0.36 1945 4.39 9 0.88 Yes Yes No No

SE = standard error; df = degrees of freedom; χ2 = chi-square