The reliability of the functional independence measure: a quantitative review

The reliability of the Functional Independence Measure (FIMSM) for adults was examined using procedures of meta-analysis.

Eleven published studies reporting estimates of reliability for the FIM were located using computer searches of Index Medicus, Psychological Abstracts, the Functional Assessment Information Service, and citation tracking.

Studies were identified and coded based on type of reliability (interrater, test-retest, or equivalence), method of data analysis, size of sample, and training or experience of raters.

Information from the articles was coded by two independent raters. Interrater reliability for coding all elements included in the analysis ranged from .89 to 1.00.

The 11 investigations included a total of 1,568 patients and produced 221 reliability coefficients. The majority of the reliability values (81%) were from interrater reliability studies, and the intraclass correlation coefficient (ICC) was the most commonly used statistical procedure to compute reliability. The reported reliability values were converted to a common correlation metric and aggregated across the 11 studies. The results revealed a median interrater reliability for the total FIM of .95 and median test-retest and equivalence reliability values of .95 and .92, respectively. The median reliability values for the six FIM subscales ranged from .95 for Self-Care to .78 for Social Cognition. For the individual FIM items, median reliability values varied from .90 for Toilet Transfer to .61 for Comprehension. Median and mean reliability coefficients for FIM motor items were generally higher than for items in the cognitive or communication subscales.

Based on the 11 studies examined in this review the FIM demonstrated acceptable reliability across a wide variety of settings, raters, and patients.