Table 2.

Outcomes of tests for DIF

HAQ-DI categories	LM	P	Abs. DIF
Rising	3.33	0.19	0.03
Walking	25.02	0.00	0.09
Dressing and grooming	71.20	0.00	0.17
Reach	37.63	0.00	0.15
Eating	6.68	0.04	0.06
Grip	2.66	0.26	0.03
Activities	51.52	0.00	0.15
Hygiene	7.29	0.03	0.06

DIF Differential item functioning, HAQ-DI Health Assessment Questionnaire Disability Index, LM Outcome Lagrange multiplier test, Abs. DIF Amount of absolute DIF d _ig

Degrees of freedom = 2