Rasch Validation of the Falls Prevention Strategies Survey

Abstract

Finlayson ML, Peterson EW, Fujimoto KA, Plow MA. Rasch validation of the Falls Prevention Strategies Survey. Objective: To validate the Falls Prevention Strategies Survey. Design: Cross-sectional descriptive survey design. With the use of Rasch analysis, the following aspects of the Falls Prevention Strategies Survey were evaluated: rating scale structure, item quality, participant fit and participant ability, invariance structure, and the potential to change in response to intervention. Setting: Community-based, national sample. Participants: Adult registrants of the North America Research Committee on Multiple Sclerosis volunteer patient registry (N=457). Interventions: Not applicable. Main Outcome Measures: The Falls Prevention Strategies Survey is a self-report instrument addressing protective behaviors related to fall risk among adults with multiple sclerosis (MS) (eg, monitoring MS symptoms, wearing proper footwear, modifying activities). Response options reflect the frequency with which the respondent engages in the behavior (ie, never, sometimes, regularly). Results: Analysis indicated that the rating scale structure (ie, response options) was valid. Of the original 19 items, 8 of them misfit and needed to be dropped to obtain a valid instrument under the Rasch model. With the final 11 items, the instrument was able to distinguish participants of different ability levels across a range of 11.58 logits. Invariance structure analysis demonstrated that the instrument functioned equally for men and women, for mobility device users and nonusers, and for participants with diagnosed MS for less than or greater than 10 years. Findings indicated that approximately 50% of respondents would have room to improve on their Falls Prevention Strategies Survey scores over time. Conclusions: Rasch analysis supports the use of the Falls Prevention Strategies Survey to examine the frequency of engaging in protective behaviors related to fall risk among adults with MS. The instrument shows potential to track outcomes of behaviorally oriented fall reduction interventions in this population. © 2009 American Congress of Rehabilitation Medicine.