Table 2.

Item parameters for healthy and chronically ill subsamples of the PedsQL™ Social subscale

								Tests for DIF: χ2 (p)
Item	Content	Subsample	a	b1	b2	b3	b4	a DIF	b DIF
1	I have trouble getting along with other kids	Healthy	2.17	−2.77	−2.29	−1.19	−0.40	3.1(.078)	7.4(.116)
	Chronically Ill	1.86	−2.78	−2.32	−1.25	−0.50
2	Other kids do not want to be my friend	Healthy	3.08	−2.29	−1.86	−1.04	−0.33	10.4(.001)	47.2(.000)
	Chronically Ill	2.23	−2.53	−2.13	−1.28	−0.65
3	Other kids tease me	Healthy	2.12	−2.25	−1.73	−0.78	−0.04	2.1(.147)	57.4(.000)
	Chronically Ill	1.84	−2.47	−1.94	−1.00	−0.43
4	I cannot do things that other kids my age can do	Healthy	1.65	−3.31	−2.53	−1.49	−0.65	2.9(.089)	56.1(.000)
	Chronically Ill	1.41	−2.85	−2.28	−1.11	−0.41
5	It is hard to keep up when I play with other kids	Healthy	1.85	−2.96	−2.41	−1.58	−0.87	24(.000)	91.8(.000)
	Chronically Ill	1.16	−3.29	−2.56	−1.23	−0.47