Reevaluating clinical measurement tools in therapeutic trials: time to make a Rasch decision?

The Science and Practice of Item Response Theory in Organizations

Item response theory (IRT) is a modeling approach that links responses to test items with underlying latent constructs through formalized statistical models. This article focuses on how IRT can be used to advance science and practice in organizations. We describe established applications of IRT as a scale development tool and new applications of IRT as a research and theory testing tool that enables organizational researchers to improve their understanding of workers and organizations. We focus on IRT models and their application in four key research and practice areas: testing, questionnaire responding, construct validation, and measurement equivalence of scores. In so doing, we highlight how novel developments in IRT such as explanatory IRT, multidimensional IRT, random item models, and more complex models of response processes such as ideal point models and tree models can potentially advance existing science and practice in these areas. As a starting point for readers interested in learning IRT and applying recent developments in IRT in their research, we provide concrete examples with data and R code.

Precision medicine in myasthenia graves: begin from the data precision

Myasthenia gravis (MG) is a prototypic autoimmune disease with overt clinical and immunological heterogeneity. The data of MG is far from individually precise now, partially due to the rarity and heterogeneity of this disease. In this review, we provide the basic insights of MG data precision, including onset age, presenting symptoms, generalization, thymus status, pathogenic autoantibodies, muscle involvement, severity and response to treatment based on references and our previous studies. Subgroups and quantitative traits of MG are discussed in the sense of data precision. The role of disease registries and scientific bases of precise analysis are also discussed to ensure better collection and analysis of MG data.

A functional scale for spinal and bulbar muscular atrophy: Cross-sectional and longitudinal study

We aimed to develop, validate, and evaluate a disease-specific outcome measure for SBMA: the Spinal and Bulbar Muscular Atrophy Functional Rating Scale (SBMAFRS). We examined the Japanese version (SBMAFRS-J) in 80 Japanese SBMA subjects to evaluate its validity and reliability. We then assessed this scale longitudinally in 41 additional SBMA subjects. The English version (SBMAFRS-E) was also tested in 15 US subjects. The total score of the SBMAFRS-J was distributed normally without an extreme ceiling or floor effect. For SBMAFRS-J, the high intra- and inter-rater agreement was confirmed (intra-class correlation coefficients [ICCs] 0.910 and 0.797, respectively), and internal consistency was satisfactory (Cronbach's alpha 0.700-0.822). In addition, SBMAFRS-J demonstrated concurrent, convergent, and discriminant validity, except for the respiratory subscale. The inter-rater reliability and internal consistency of SBMAFRS-E were also satisfactory. Longitudinally, SBMAFRS-J showed a higher sensitivity to disease progression than the existing clinical measures. In conclusion, we developed and validated a disease-specific functional rating scale for SBMA in both Japanese and English versions, although it needs to be re-assessed in interventional studies with a larger sample size including English speaking subjects.