Validation of an independent living scale for post-acute rehabilitation applications

The Independent Living Scale (ILS) was developed in a post-acute traumatic brain injury (TBI) rehabilitation facility over a 15-year period to assess three main areas: (1) activities of daily living, (2) behaviour, and (3) initiation. The purpose of this study was to examine the psychometric properties of the ILS, including test--retest stability, construct validity, and statistical fit. Statistical analysis was completed on all weekly scores between the years 1986-1995 (n = 5250). A previous study showed ILS inter-rater reliability to be 0.85 and convergent validity 0.82--0.87. This study demonstrated a test--retest stability of 0.72, the Kaiser-Meyer-Olkin Measure of Sampling Adequacy 0.94 (marvelous), and a Bartlett Test of Sphericity result of 'scale items independent'. The ILS was shown to have good construct validity, inter-rater reliability, internal consistency, instrument stability, and convergent validity.