Table 6.

Differential Item Functioning (DIF) of Age (above and below the Median Age) for the AS-20 Self-Perception, Interaction, Reading Function, and General Function Subscales

Item #	< Median Age		> Median Age
	DIF Measure	SE	DIF Measure	SE	DIF Contrast
Self-perception subscale
1	0.11	0.14	0.06	0.15	0.06
2	−0.38	0.14	−0.15	0.15	−0.23
3	−0.12	0.14	−0.40	0.16	0.27
4	−0.50	0.14	−0.55	0.16	0.05
6	0.89	0.14	1.02	0.15	−0.14
Interaction subscale
5	−1.06	0.13	−0.68	0.17	−0.38
7	−0.23	0.12	−0.42	0.16	0.19
8	0.36	0.12	0.46	0.15	−0.10
9	0.25	0.12	0.25	0.15	0.00
10	0.65	0.12	0.42	0.15	0.23
Reading function subscale
12	−0.96	0.14	−0.82	0.14	−0.14
13	−0.25	0.13	−1.00	0.14	0.75*
16	0.77	0.13	0.92	0.14	−0.15
20	0.43	0.13	0.92	0.14	−0.49
General function subscale
11	−0.40	0.13	0.25	0.13	−0.65*
15	0.41	0.12	0.12	0.13	0.29
17	−0.52	0.13	−0.52	0.13	0.00
18	0.49	0.12	0.17	0.13	0.32

^* Minimal differential item functioning was found between individuals < median age and individuals > median age for items #11 and #13, but these items were retained.