From p.56 of Bond & Fox (2007):
Results produced by the program; compare "Rasch Diff" below with "Difficulty Estimate" above:
Item |
CTT Diff |
Rasch Diff |
Error |
Infit |
Outfit |
V1 |
0.86 |
-0.79 |
0.26 |
0.98 |
0.69 |
V2 |
0.86 |
-0.72 |
0.26 |
1.01 |
0.75 |
V3 |
0.65 |
0.76 |
0.20 |
0.98 |
0.90 |
V4 |
0.77 |
0.00 |
0.22 |
1.00 |
0.88 |
V5 |
0.88 |
-1.01 |
0.28 |
0.98 |
0.76 |
V6 |
0.97 |
-2.49 |
0.47 |
1.06 |
0.83 |
V7 |
0.85 |
-0.66 |
0.25 |
0.97 |
0.65 |
V8 |
0.63 |
0.88 |
0.19 |
0.91 |
1.00 |
V9 |
0.74 |
0.18 |
0.21 |
1.07 |
0.97 |
V10 |
0.80 |
-0.20 |
0.23 |
0.92 |
0.68 |
V11 |
0.74 |
0.18 |
0.21 |
1.02 |
0.96 |
V12 |
0.94 |
-1.81 |
0.36 |
0.69 |
0.24 |
V13 |
0.60 |
1.03 |
0.19 |
1.16 |
1.32 |
V14 |
0.86 |
-0.72 |
0.26 |
1.15 |
1.32 |
V15 |
0.60 |
1.03 |
0.19 |
0.97 |
0.84 |
V16 |
0.81 |
-0.31 |
0.23 |
1.13 |
1.03 |
V17 |
0.71 |
0.40 |
0.20 |
0.87 |
0.75 |
V18 |
0.78 |
-0.05 |
0.22 |
0.90 |
0.74 |
V19 |
0.69 |
0.48 |
0.20 |
1.01 |
1.05 |
V20 |
0.87 |
-0.86 |
0.27 |
0.91 |
0.81 |
V21 |
0.35 |
2.40 |
0.20 |
1.27 |
1.75 |
V22 |
0.89 |
-1.09 |
0.29 |
0.91 |
1.69 |
V23 |
0.71 |
0.36 |
0.21 |
1.06 |
0.92 |
V24 |
0.73 |
0.23 |
0.21 |
0.89 |
1.03 |
V25 |
0.69 |
0.52 |
0.20 |
1.07 |
1.26 |
V26 |
0.64 |
0.80 |
0.20 |
0.90 |
0.75 |
V27 |
0.88 |
-0.94 |
0.27 |
0.85 |
0.62 |
V28 |
0.48 |
1.68 |
0.19 |
1.12 |
1.23 |
V29 |
0.83 |
-0.47 |
0.24 |
0.94 |
0.71 |
V30 |
0.59 |
1.10 |
0.19 |
1.19 |
1.15 |
V31 |
0.74 |
0.18 |
0.21 |
1.07 |
1.55 |
V32 |
0.57 |
1.17 |
0.19 |
0.96 |
0.85 |
V33 |
0.84 |
-0.53 |
0.25 |
1.10 |
0.93 |
V34 |
0.82 |
-0.42 |
0.24 |
1.00 |
0.79 |
V35 |
0.81 |
-0.31 |
0.23 |
0.93 |
0.73 |
Average: |
0.75 |
0.00 |
0.24 |
1.00 |
0.95 |
Median: |
0.77 |
0.00 |
0.22 |
0.98 |
0.88 |
s.d.: |
0.13 |
0.97 |
0.05 |
0.11 |
0.31 |