extended · article · 2026

Category-Based Interlaboratory Comparisons: Psychometric Rasch Analyses Defining Reference Values and Statistical Weighting in a Clinical Example

Leslie Pendrill; William P. Fisher Jr.

The Rasch model is not mathematically limited to psychometrics or human respondents; but should also be applicable to more technical agents. This work, as a bridging exercise exploiting this agnostic aspect, explores how psychometric tools can support a major activity in metrology across the disciplines: namely, Interlaboratory Comparisons (ILCs), where one or more common objects are circulated for measurement amongst several laboratories, as a regular tool for assessing performance. ILCs are less developed for ordinal and nominal data and have been rarely studied to date in the human sciences. The present clinical case study examines whether the performance of different surgical interventions—specifically based on carotid artery stenosis outcomes—can be interpreted in terms of metrological ILCs using Rasch psychometric modelling as an alternative to earlier Generalised Linear Mixed Mode...