Evaluation of the Unidimensional Fatigue Impact Scale (U-FIS) in Crohn's Disease: The Importance of Local Item Dependency

Background and PurposeThe Unidimensional Fatigue Impact Scale (U-FIS) was developed for use in a multiple sclerosis population. The aim was to determine whether the U-FIS is a valid tool for measuring the impact of fatigue in Crohn's disease (CD).MethodCD patients completed the U-FIS as part of a validation study of the Crohn's Life Impact Questionnaire (CLIQ). Data were analyzed according to Rasch measurement theory (RMT).ResultsTwo hundred sixty-one completed U-FIS questionnaires were available for analysis. After rescoring the items to resolve disordered thresholds, all 22 items showed acceptable RMT fit. However, there was considerable local item dependency (LID).ConclusionThe U-FIS did not provide unidimensional measurement in a sample of CD patients due to high levels of LID. Combining the three FIS outcomes into a single measure was not justified.

The client satisfaction with device: a Rasch validation of the Arabic version in patients with upper and lower limb amputation

Background The Client Satisfaction with Devices (CSD) module of the Orthotics and Prosthetics Users’ Survey is an extensively used questionnaire that measures patients’ satisfaction with orthosis and prosthesis. However, the validated version for Arabic speakers (CSD-Ar) is only applicable for orthosis users. Objectives The aim of this study was to evaluate the psychometric proprieties of the CSD-Ar for prosthetics users. Methods The study used a convenience sample of prosthesis users from Saudi Arabia and Turkey (N = 183), who completed the CSD-Ar. The collected data were analysed using Rasch analysis to evaluate item fit, reliability indices, item difficulty, local item dependency, and differential item functioning (DIF) using WINSTEPS version 4.6.1. Results Based on the analysis, the four-response Likert-scale was acceptable, as shown by the category functioning test, All eight items did achieve a fit to the Rasch Model [(infit) and (outfit) mean-square 0.75 to 1.3]. Person separation reliability was 0.76, and item separation reliability was 0.94. A principal component analysis (PCA) showed satisfactory unidimensionality and no local item dependency. The DIF analysis showed no notable dependency among items on participant characteristics in terms of age, gender, duration of use, country, and level of amputation. Conclusion This study contributes to the confidence of using CSD-Ar to evaluate users’ satisfaction with different prostheses, affirming the need for further refinement of the quality of the outcome measure.

A Rasch analysis of emerging adults’ health motivation questionnaire in higher education context

Objective The College Students’ Health Motivation Questionnaire (CSHM-Q) is used to measure motivation for a healthy lifestyle among emerging adults. This study sought to validate the CSHM-Q using the Rasch measurement model. Methods 322 participants were recruited based on a convenience sampling method. The Rasch analysis was carried out using the RUMM2030 software. Results Local item dependency was accommodated using the ‘super item’ approach. Disordered thresholds were resolved by collapsing some response options. After modification, each component of the CSHM-Q showed acceptable overall fit, item and person fit, internal consistency, and targeting. Unidimensionality was supported at the subscale level. Items did not exhibit disordered threshold, local item dependency, or differential item functioning. Transforming tables were also created to help convert the raw score into an interval scale. Conclusions Results of the Rasch analysis supported the interval scale measurement properties of the CSHM-Q and offered health education researchers an instrument to measure emerging adults’ health motivation in the higher education context.