Table 2.

Summary item statistics of the analyses for the version with 12 items.

Items	Location	2 SE	Fit residuals	Chi-square (df=2)	P value	Testlet
It was a disturbance	−1.20	0.37	1.97	2.30	.32	1
It interrupted me in my daily activities	—a	—	—	—	—	—
It was too time consuming	−1.03	0.36	0.97	2.33	.31	1
The introduction of how to use it was sufficient	−0.53	0.38	1.46	0.87	.65	2
It was boring to use	−0.44	0.30	2.52	2.96	.23	1
It was easy to use	−0.37	0.37	−0.90	1.58	.45	2
It was good to use	−0.08	0.45	−1.38	2.86	.24	2
The time spent using it has been acceptable	0.09	0.41	−0.77	0.66	.72	2
I can recommend it to others	0.38	0.37	−0.82	1.98	.37	2
It has been difficult to remember to use it	—	—	—	—	—	—
It has motivated me to change my lifestyle habits	0.72	0.39	−2.02	3.93	.14	3
It has helped me to understand the benefits of improving my lifestyle habits	0.73	0.40	−2.44	3.01	.22	3
It has helped me to understand how I need to change my lifestyle habits	0.78	0.40	−2.66	1.98	.37	3
It has helped me set personal goals for my lifestyle habits in a way that I could not have done on my own	0.94	0.38	−1.01	1.11	.57	3

^aThe items have been removed.