Does the falls efficacy scale international version measure fear of falling: a reassessment of internal validity using a factor analytic approach.

BACKGROUND the Falls Efficacy Scale-International (FES-I) is a widely used measure of fear of falling that assesses concerns with respect to falls over a range of physical and social activities. In the original validation study, the methods used (self-selection by participants) were likely to over-represent those with a higher educational level and socio-economic grouping. In addition, the factor analysis method used was potentially less applicable to older individuals and may have been less likely to measure the construct of fear of falling. OBJECTIVE to validate the internal validity of the FES-I and assess its suitability as a measure of fear of falling. DESIGN cross-sectional survey. SETTING community sample. METHODS a random sample of 200 participants aged 60 years completed the FES-I by structured interview. We verify internal validity with a factor analytic approach not previously employed in this study design context, principal factor analysis on the matrix of polychoric correlations. RESULTS we find no redundancy in the questions on the FES-I. All are found to strongly represent concerns about falling during social and physical activities. CONCLUSION the FES-I is an appropriate tool to assess fear or concerns with respect to falls in the general elderly population, and more appropriately represents concern of falling than has previously been found. Future health services research with the FES-I should have its design informed by the results presented in this study, as the structure of the 'concern with falling' factor differs markedly from that found in previous validity testing.