The Independent Living Scale (ILS) is an observational task analysis tool in which data about the client is collected over a 7-day period by examining 3 domains of occupational performance: (1) activities of daily living (ADLs), (2) behavior and, (3) initiation. The ILS is composed of 5 scales: (1) memory-orientation, which examines orientation, recall, and recognition; (2) managing money; (3) managing home and transportation; (4) health and safety; and (5) social adjustment, which explores one’s interpersonal relationships (Revheim & Medalia, 2004). The assessment is composed of 68 items that are graded relative to subject performance along a 3-point scale from 0 to 2 (Fish, 2011). Results of the ILS yield 5 subscale scores and a total score (0 to 100) as well as 2 additional subscales whose scores are derived from those of the 68 items: a performance-information factor subscale, which reflects the skills needed for task performance, such as using a telephone book or making change, and a problem-solving factor subscale, which comprises 33 items that evaluate abstract reasoning and judgment required for daily living and explores such questions as, “What would you do if your lights and television went out simultaneously?” (Revheim & Medalia, 2004). ILS scoring uses a factor system where each item is uniquely weighted relative to its importance. For example, dressing has a value of 5 points out of the 61 sub-scale points where it resides, whereas leisure only has a value of 2 points (Revheim & Medalia, 2004). The assessment can be completed in less than 45 minutes.
A study by Ashley, Persel, and Clark (2001) of 5290 traumatic brain injury (TBI) subjects admitted to a post-acute rehabilitation facility over a 15-year period demonstrated a test-retest reliability of r = 0.72. While citing prior work with the ILS of 77 subjects, they found total inter-rater reliability to be good at r = 0.85, whereas inter-rater reliability was 0.7 for the behavior sub-scale, and 0.93 for the ADL subscale. Good convergent validity was also noted as well between 0.82 to 0.87 as significant correlations were found with the Vineland Adaptive Behaviour Scale (0.82), and with the American Association for Mental Deficiency Adaptive Behavior Scales (0.87). Finally, statistical fit using a four-factor model, they determined that for the self-care model the fit was 0.50, directed aggression was 0.79, environmental care was 0.80, and for protective task avoidance it was 0.65, suggesting that these four factors are consistent with clinical observations of skill necessary for independent living (Ashley et al., 2001). Among 40 clients of mixed diagnoses (TBI, cerebrovascular accident, multiple sclerosis) in an acute neurological rehabilitation hospital, the ILS had a modest correlation with Functional Independence Measure (FIM) discharge scores at 0.39 (Gillen & Gernert-Dott, 2000). The same study found that correlations between individual subtests of the ILS with FIM discharge scores varied from 0.47 for the management of home and transportation scale, 0.44 for health and safety scale, to minimal (r = 0.80, p =0.673) for the memory/orientation scale (Gillen & Gernert-Dott, 2000). Assessing the validity of the ILS among persons with schizophrenia (n = 162), Revheim and Medalia (2004) determined that scores on the ILS problem solving subscale differed significantly across 3 levels of care for persons requiring maximum, moderate, and minimal supervision when compared with scores on the Global Assessment of Functioning measure, which was only able to discriminate between 2 levels of care.
n = 162; ages 18 to 52 years old
Adapted from Revheim, N., & Medalia, A. (2004). The Independent Living Scales as a measure of functional outcome for schizophrenia. Psychiatric Services, 55(9), 1053.