Development and preliminary validation of a new scale to assess functional ability of older population in India

Abstract

Identifying the decline in functional ability and preventing disability is the critical element of the quality of life of an old age. However, the lack of contextual scale to assess the decline in functional capacity is a major issue. Objective of this study is to design the functional ability assessment scale for elderly people in India and test its psychometric properties. Random sample of 659 individuals above 60 years of age from western part of India was recruited. This paper outlines the construction, reliability and validity of a newly developed 14 item scale named as Pune-Functional Ability Assessment Tool (Pune-FAAT). The factors were extracted using the principal component analysis. Two-factor-structure of scale was accepted after applying the K1 rule, scree plot and parallel analysis method. The two factor structure yielded variance of 64.4%. The psychometric properties of the scale were examined using confirmatory factor analysis. The scale has an excellent reliability (Cronbach's α 0.928) and very good test-retest reliability (r=0.884). Each subscale demonstrated good internal consistency (Subscale I - Cronbach's α 0.938 and Subscale II - Cronbach's α 0.762). Excellent convergent validity with Standford's health assessment questionnaire (r=0.959). Discriminant validity was very good as FAAT index showed significant difference in young adults (mean±SD 1.11±0.24) and older adults (mean±SD 1.69±0.70). This new measure is a potentially valuable research tool for investigating older adult's functional ability to perform basic and complex daily activities.

Keywords: Elderly; Functional ability tool; India; Pune-FAAT; Reliability; Validity.