Table 3.

Psychometric properties of the Yale Food Addiction Scale for children in item levels

Item #	Analyses from classical test theory			Analyses from item response theory
	Factor loadinga	Item total correlation	Test–retest reliabilityb	Infit MnSq	Outfit MnSq	Difficulty	Discrimination	DIF contrast across genderc,d	DIF contrast across weight statusc,e
#1	0.41	0.49	0.73	1.03	0.88	− 0.11	1.17	− 0.17	0.31
#2	0.53	0.50	0.78	0.88	0.73	− 0.16	1.14	0.21	0.49
#3	0.51	0.46	0.74	0.95	0.96	− 0.75	0.96	0.01	0.33
#4	0.44	0.42	0.83	1.12	1.04	− 0.30	0.89	0.24	0.12
#5	0.43	0.45	0.84	0.94	0.85	− 1.52	0.87	0.43	0.24
#6	0.53	0.52	0.88	0.96	0.59	0.57	1.00	− 0.23	0.33
#7	0.63	0.46	0.92	1.08	1.29	− 0.63	0.81	0.27	− 0.30
#8	0.69	0.60	0.76	0.89	0.74	− 0.30	1.08	0.19	− 0.22
#9	0.70	0.64	0.80	0.75	0.58	0.93	1.13	0.44	0.21
#10	0.51	0.54	0.86	0.96	0.68	− 0.35	1.03	0.16	0.45
#11	0.55	0.54	0.94	0.96	0.82	− 0.12	1.01	0.43	0.49
#12	0.69	0.58	0.88	0.85	0.52	0.82	1.09	− 0.47	0.23
#13	0.70	0.57	0.72	0.92	0.70	0.15	1.05	− 0.27	0.41
#14	0.68	0.59	0.70	0.91	0.64	− 0.08	1.17	− 0.39	− 0.22
#15	0.66	0.60	0.76	0.89	0.58	− 0.15	1.08	0.34	− 0.43
#16	0.64	0.57	0.72	0.88	0.65	0.84	1.03	0.09	− 0.14
#17	0.49	0.41	0.82	1.10	1.55	1.35	1.17	0.41	− 0.42
#18	0.46	0.40	0.75	1.09	1.02	1.39	1.19	0.01	− 0.34
#21	0.40	0.40	0.73	1.26	1.49	− 2.90	1.15	0.43	− 0.39
#22	0.41	0.42	0.79	1.16	1.47	− 3.02	1.34	0.21	− 0.46
#23	0.44	0.48	0.82	1.20	1.17	0.19	1.31	− 0.24	− 0.17
#25	0.57	0.41	0.77	1.24	1.33	− 1.01	0.35	− 0.41	0.38

MnSq mean square error, DIF differential item functioning

^aBased on confirmatory factor analysis

^bUsing intraclass correlation coefficient

^cDIF contrast > 0.5 indicates substantial DIF

^dDIF contrast across gender = difficulty for females − difficulty for males

^eDIF contrast across weight status = difficulty for participants with obesity − difficulty for participants with overweight