Table 4.

Global physical health scale item parameters (graded response model) and item information

	a	b1	b2	b3	b4	Information
Global03	2.31	−2.11	−0.89	0.29	1.54	1.39
Global06	2.99	−2.80	−1.78	−1.04	−0.40	1.87
Global07	1.74	−3.87	−1.81	−0.67	1.00	0.81
Global08	1.90	−3.24	−1.88	−0.36	1.17	0.94

Item 1: Global03, In general, how would you rate your physical health?; Item 2: Global06, To what extent are you able to carry out your everyday physical activities?; Item 3: Global07, How would you rate your pain on average?; Item 4: Global08, How would you rate your fatigue on average?