Thought it could be helpful to have a thread on Jonathan's expert testimony for any further use and citation. Edwards, Jonathan CW (2020), The difficulties of conducting intervention trials for the treatment of myalgic encephalomyelitis/chronic fatigue syndrome: Expert testimony presented to the NICE guideline committee, 06.09.2019, https://www.nice.org.uk/guidance/GID-NG10091/documents/supporting-documentation-3 Summary Therapeutic trials for ME/CFS are particularly at risk from expectation bias because of the subjective core features and fluctuating nature of the illness. Therapist-delivered treatments, with lack of blinding, and particularly those involving cognitive intervention, are even more at risk because of role-playing and deliberate influence on attitudes to health status. Trials of drug treatments have tended to navigate difficulties adequately but have yielded negative (or equivocal) results. Trials of therapist-delivered treatments to date have not met basic requirements for minimising bias and are therefore unsuitable as an evidence base for treatment recommendations. Inasmuch as they are interpretable, they suggest that although attitudes to health status maybe influenced this does not lead to significant improvement in objectively measures of disability. There are also specific ethical concerns with trials of treatments that aim to persuade patients of an unproven theoretical model for their illness and for which there is prima facie evidence of significant harm (for exercise therapy). The failure to meet basic requirements indicates a problem with quality control through peer review in this area, as illustrated with problems with Cochrane reviews (see bibliography: Vink and Vink-Niese, 2018; Vink and Vink-Niese, 2019). Trials to date have failed to make use of methods that can significantly mitigate difficulties with bias from subjective outcomes, but it may be that for unblindable treatments new forms of trial methodology will be needed if useful assessment is to be achieved. In my view, the uninterpretability of evidence from trials that fail to overcome basic difficulties, combined with ethical concerns, means that it is inappropriate to recommend either cognitive behavioural therapy or exercise therapies for ME/CFS. (Paragraphing inserted.) Please let me know if the title/ citation needs any correction. Also, feel free to move it to another place. Perhaps a new subforum on trial methodology added to 'ME/CFS News and Research' forums could be a good thing?