Application of the Rasch measurement model in rehabilitation research and practice: early developments, current practice, and future challenges

Abstract

The application of the Rasch measurement model in rehabilitation is now well established. Both its dichotomous and polytomous forms provide for transforming ordinal scales into interval-level measures, consistent with the requirements of fundamental measurement. The growth of applying the model in rehabilitation spans 30 years, during which both the protocol has steadily developed and several software packages have emerged that provide for analysis, together with the “R” language that has an increasing set of codes for applying the model. This article reviews that development and highlights current practice requirements, including those for providing the relevant information for the methods, and what is expected of the analysis. In addition, this provides a worked example and looks at the remaining issues and current developments of its application.

Psychometric testing of the Rheumatoid Arthritis Work Instability Scale in employed people with fibromyalgia

“…Here, he introduced a model for dichotomous responses in a test, subsequently written as an "additive logistic model," which is the form widely reported today (Kreiner, 2013). The model states that the probability of obtaining a correct response to an item, given the ability level of the person, is a logistic function of the difference between the ability of the person and the difficulty of the test item (Tennant & Küçükdeveci, 2023). In the context of work instability, this would mean that the probability of a person with FM affirming an item on the RA-WIS would represent the difference between their level of work instability and the level of instability represented by the item.…”

“…For which results ≥0.80 are deemed good to excellent, with ≥0.90 being consistent with individual use; and >0.70 with group-level use (Evans, 1996); and (b) the Person Separation Index (PSI) for which scores >0.70 also indicate group-level use; and ≥0.85 individual use (Tennant & Küçükdeveci, 2023).…”

Rasch analysis of the self efficacy (SE-12) questionnaire measuring clinical communication skills

“…By transforming ordinal data into interval-level measurements, Rasch analysis provides a detailed assessment of a measure's validity, dimensionality, and reliability. This method provides a more accurate and meaningful analysis, facilitating the identification of nuanced changes in self-efficacy [ [24] , [25] , [26] , [27] ].…”