Table 3.

Agreement (ICC, 95% CI) between observed and predicted total scale scores using crosswalks based on the different IRT models in the calibration sample (n = 1791)

	Rasch	Two-parameter	Multi-dimensional
	model	model	model
HAQ-SDI	0.739 (0.717 to 0.760)	0.741 (0.719 to 0.762)	0.739 (0.717 to 0.760)
HAQ-ADI	0.737 (0.714 to 0.758)	0.737 (0.715 to 0.758)	0.735 (0.712 to 0.756)
PF-10 (predicted from HAQ-SDI)	0.746 (0.724 to 0.767)	0.745 (0.722 to 0.765)	0.742 (0.720 to 0.763)
PF-10 (predicted from HAQ-ADI)	0.748 (0.726 to 0.768)	0.750 (0.728 to 0.770)	0.749 (0.727 to 0.769)

ICC = intraclass correlation coefficient; HAQ-SDI = Health Assessment Questionnaire standard disability index; HAQ-ADI = Health Assessment Questionnaire alternative disability index; PF-10 = SF-36 physical functioning scale.