Table 2.

Item Parameters for Two 4-Item Variants of Global Physical Health (Graded Response Model)

	a	b1	b2	b3	b4
Global03	2.31	−2.11	−0.89	0.29	1.54
Global01*	2.31	−2.21	−1.01	0.17	1.46
Global06	2.99	−2.80	−1.78	−1.04	−0.40
Global06*	2.99	−2.80	−1.78	−1.05	−0.40
Global07	1.74	−3.87	−1.81	−0.67	1.00
Global07*	1.76	−3.86	−1.80	−0.67	0.99
Global08	1.90	−3.24	−1.88	−0.36	1.17
Global08*	1.88	−3.26	−1.89	−0.36	1.17

Global01: In general, how would you rate your health? Excellent, Very Good, Good, Fair, Poor; Global03: In general, how would you rate your physical health? Excellent, Very Good, Good, Fair, Poor; Global06: To what extent are you able to carry out your everyday physical activities such as walking, climbing stairs, carrying groceries, or moving a chair? Completely, Mostly, Moderately, A little, Not at all; Global07: In the past 7 days, how would you rate your pain on average? Scale of 0–10, where 0 = no pain and 10 = worst pain imaginable; Global08: In the past 7 days, how would you rate your fatigue on average? None, Mild, Moderate, Severe, Very severe

a = discrimination parameter; b1–b4 are threshold parameters

* Indicates calibrations based on substituting global01 for global03