Table 4.

Item Response Theory model parameters from C-eHEALS Graded Response Modelsa.

C-eHEALS items	Discrimination				Difficulty
	alpha	SD	P value	betaMb	beta1	beta2	beta3	beta4
C-eHEALS1	1.46	0.15	<.001	–0.47	–3.18	–1.96	–0.01	3.26
C-eHEALS2	1.74	0.17	<.001	–0.43	–2.97	–1.77	0.33	2.67
C-eHEALS3	2.31	0.23	<.001	–0.53	–2.86	–1.72	0.06	2.39
C-eHEALS4	1.72	0.16	<.001	–0.51	–3.24	–1.59	0.23	2.57
C-eHEALS5	1.81	0.16	<.001	–0.69	–3.28	–1.70	–0.08	2.31
C-eHEALS6	1.32	0.13	<.001	–0.54	–3.30	–1.78	0.25	2.68
C-eHEALS7	1.55	0.15	<.001	–0.56	–3.58	–1.63	0.25	2.73
C-eHEALS8	1.43	0.14	<.001	–0.38	–2.97	–1.49	0.35	2.59

^aDiscrimination (alpha) refers to an item’s ability to discriminate between different latent levels of eHealth literacy (ie, theta). Difficulty parameters (beta) for responses on the 5-point Likert-type scale: 1 (from “strongly disagree” to “disagree”), 2 (from “disagree” to “neutral”), 3 (from “neutral” to “agree”), and 4 (from “agree” to “strongly agree”).

^bBeta_M: mean beta.