From: Using item response theory to enrich and expand the PROMIS® pediatric self report banks
DIF between | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Item parameters | S-X2fit index | Boys and Girls | Ages | |||||||||
Item Stem | a | b 1 | b 2 | b 3 | b 4 | X 2 | d.f. | p | X 2 | p | X 2 | p |
Added to the Upper Extremity item bank: | ||||||||||||
I could pick up coins from a table. | 2.94 | -3.23 | -2.66 | -1.87 | 10 | 8 | 0.247 | 3.8 | 0.291†† | 2.9 | 0.406†† | |
I could wash my hair by myself. | 2.14 | -2.84 | -2.37 | -1.61 | 18 | 22 | 0.731 | 1.3 | 0.861† | 5.4 | 0.253† | |
I could put beads on a string.* | 1.95 | ?3.32 | ?3.04 | ?2.41 | ?1.56 | 30 | 23 | 0.151 | 6.3 | 0.283 | 5.9 | 0.212† |
I could comb my hair by myself. | 2.43 | ?3.25 | ?2.8 | ?2.59 | ?1.65 | 19 | 14 | 0.160 | 3.9 | 0.269†† | 5 | 0.286† |
I could thread a needle.* | 1.54 | -2.14 | -2.02 | -1.43 | -0.57 | 50 | 41 | 0.162 | 9.7 | 0.083 | 12.1 | 0.034 |
Added to the Mobility item bank: | ||||||||||||
I could jump up and down. | 2.93 | -2.3 | -2.06 | -1.7 | -1.16 | 73 | 43 | 0.003 | 4.1 | 0.539 | 2.5 | 0.774 |
Not added to the Mobility item bank (DIF): | ||||||||||||
I could get in and out of a chair on my own. | 3.46 | -3.06 | -2.79 | -2.38 | -1.78 | 32 | 16 | 0.010 | 3.3 | 0.657 | 24.6 | 0.001 |
Not added to the Mobility item bank (LD and DIF): | ||||||||||||
I could run three miles without stopping. | 1.51 | -0.52 | 0.04 | 1.04 | 1.74 | 52 | 57 | 0.678 | 14.8 | 0.011 | 7.6 | 0.176 |