Carr, Ewan, Vitoratou, Silia, Chalder, Trudie et al. · Journal of psychosomatic research · 2021 · DOI
Researchers wanted to check whether different questionnaires used in ME/CFS studies were actually measuring different things. They looked at data from 640 people in a large treatment trial and used statistical methods to see if the questions meant to measure thinking/behavior problems overlapped too much with questions measuring physical function and fatigue. They found that most of the questionnaires were measuring distinct concepts, which means the study design was solid.
Understanding whether research questionnaires measure different concepts is crucial for interpreting study results. This work validates that mediation analyses in ME/CFS trials—which attempt to explain how treatments work—are built on questionnaires that genuinely measure separate things, strengthening confidence in conclusions about treatment mechanisms.
This study does not prove that any particular ME/CFS treatment is effective, nor does it establish whether the mediators actually cause changes in fatigue or physical function. It only confirms that the measurement tools are distinct enough to be used together in analyses; it says nothing about whether the proposed causal pathways in PACE or other trials are correct.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Carr, Ewan, Vitoratou, Silia, Chalder, Trudie, & Goldsmith, Kimberley (2021). Discernment of mediator and outcome measurement in the PACE trial.. Journal of psychosomatic research. https://doi.org/10.1016/j.jpsychores.2021.110595
BibTeX
@article{mecfsatlas-carr-2021-discernment-mediator,
author = {Carr, Ewan and Vitoratou, Silia and Chalder, Trudie and Goldsmith, Kimberley},
title = {Discernment of mediator and outcome measurement in the PACE trial.},
journal = {Journal of psychosomatic research},
year = {2021},
doi = {10.1016/j.jpsychores.2021.110595},
note = {PubMed: 34438356},
url = {https://www.mecfsatlas.com/evidence/carr-2021-discernment-mediator},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-25. https://www.mecfsatlas.com/evidence/carr-2021-discernment-mediator
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