MEASUREMENT PROPERTIES OF THE RM-18 - A MODIFIED VERSION OF THE ROLAND-MORRIS DISABILITY SCALE

Study Design. This investigation had two components: one was an item a nalysis that examined data obtained at the initial patient assessment, and the second was a validation study that used a pretest-posttest de sign. Objectives, The authors' goal, in this study, was to determine w hether a shorter version of the Roland-Morris Questionnaire could be d eveloped with measurement properties equal to or better than the origi nal 24-item questionnaire. Summary of Background Data, The measurement properties of the Roland-Morris Questionnaire have been shown to be b etter than or equal to competing measures. A number of studies have re ported modified versions of the Roland-Morris without providing the me asurement properties of the modified tool. Methods. The item analysis investigated endorsement frequency, interitem correlations, item-corre cted item total correlations, and coefficient alpha with various combi nations of items deleted. The validation study examined reliability, c oncurrent validity, and longitudinal Validity (sensitivity to change). The analyses in eluded comparisons with the Oswestry and Jan van Bree man Pain Questionnaires. Results. The item analysis suggested than six items could be deleted from the Roland-Morris Questionnaire. The vali dation study demonstrated that the shorter version, named the RM-18, h as measurement properties that are equal to those of the longer versio n. Conclusions. The RM-18 can be used as an outcome measure in clinica l trials or as a tool to aid in decision making concerning individual patients. In either case, its measurement properties are equal to thos e of the 24-item Roland-Morris Questionnaire.