From: Rasch analysis of the Brain Injury Screening Tool (BIST) in mild traumatic brain injury
Analyses | Item fit residual | Person fit residual | Item-trait Interaction | PSIa | Cronbach’s alpha | Unidimensional (sig. t-test % p < 0.05) (95% CI) | Local dependency | ||||
---|---|---|---|---|---|---|---|---|---|---|---|
Value | SD | Value | SD | χ2 | df | p | α | ||||
Pathway 1: All 15 items | 0.10 | 0.89 | −0.18 | 1.13 | 21.67 | 30 | 0.87 | 0.91 | 0.93 | No (> 7) | Yes |
Pathway 2: Combined Cognitive symptoms subtest (items 8,9,10,11) | 0.26 | 0.86 | −0.11 | 1.00 | 26.84 | 24 | 0.31 | 0.90 | 0.86 | No (> 7) | Yes |
Pathway 3: Three Subtests | 0.04 | 1.13 | −0.38 | 0.97 | 3.67 | 6 | 0.72 | 0.84 | 0.77 | Yes (4.55) | Yes |
Subtest 1: Physical-Emotional symptoms (Items 1,2,3,4,12,13,14,15) | 0.12 | 0.97 | −0.15 | 0.88 | 7.20 | 16 | 0.97 | 0.85 | 0.88 | Yes (4.55) | No |
Subtest 2: Vestibular-Ocular symptoms (Items 5,6,7) | 0.51 | 0.40 | −0.21 | 0.88 | 5.46 | 6 | 0.49 | 0.41 | 0.57 | Yes (0.00) | No |
Subtest 3: Cognitive symptoms (Items 8,9,10,11) | 0.19 | 0.23 | −0.33 | 0.91 | 1.86 | 8 | 0.99 | 0.83 | 0.85 | Yes (0.91) | Yes |
Ideal values | 0.00 | 1.0 | 0.00 | 1.0 | > 0.05b | > 0.7 | < 5 |