Inter-rater agreement and stability of functional assessment in the community-based elderly

The purpose was to examine the inter-rater agreement and test-retest stability of the Functional Independence Measure (FIM) and the Instrumental Activities of Daily Living Scale (IADL) from the Multidimensional Functional Assessment of Older Adults. These two instruments were administered to 20 older persons living in the community. Two experienced raters administered the assessment instruments over either a short (7-10 days) or long (4 to 6 week) interval. The intraclass correlation (ICC) was used to analyze the data. ICC values were computed for agreement between and within raters and across short and long intervals. ICC values for inter-rater agreement and stability ranged from 0.90 to 0.99. The relation between scores on the FIM and IADL scale was also examined. The analysis produced an r value of 0.85, suggesting a positive statistical relationship among the items assessed. The high ICC values indicate that the Functional Independence Measure Instrument and IADL scale of the Multidimensional Functional Assessment of Older Adults provide consistent information across two experienced raters and over time when used with a sample of elderly persons residing in the community.