The Academic Medical Center Linear Disability Score (ALDS) item bank: item response theory analysis in a mixed patient population

Table 1 characteristics of the 6 sets of items

Item set	n	Population	Total number of items	Number of clinically relevant items	Number of items after analysis	Cronbach's alpha coefficient	Number of latent roots > 1	Variance explained by a single factor
A	235	Chronic pain	88	58	39	0.94	3	64%
B	127	Stroke	21	19	14	0.92	1	77%
C	179	RC + PD*	80	52	32	0.96	2	77%
D	164	RC + PD*	80	54	41	0.96	2	73%
E	157	RC + PD*	80	55	43	0.97	3	72%
F	140	RC + PD*	80	55	36	0.96	3	75%
All	1002		170	115	78	0.98	5	77%

ISSN: 1477-7525