When the Protocol was designed, the researchers analysed previous research, including their own, into GET and CBT for ME/CFS. This informed their choice of the Outcome Measures.
The Protocol states: “We have chosen 15 sessions for all supplementary treatments on the basis of the previous trials of CBT and GET [18,23-26], as well as extensive clinical experience.” And: “The existing evidence does not allow precise estimates of improvement with the trial treatments. However the available data suggests that at one year follow up, 50 to 63% of participants with CFS/ME had a positive outcome, by intention to treat, in the three RCTs of rehabilitative CBT [18,25,26], with 69% improved after an educational rehabilitation that closely resembled CBT [43]. This compares to 18 and 63% improved in the two RCTs of GET [23,24], and 47% improvement in a clinical audit of GET [56].”
Therefore the Primary Outcome Measures in the Protocol were based on existing research, including that done by the Principal Investigators themselves and on their “extensive clinical experience”. Why would these experienced physicians and researchers believe it was necessary to lower their own target thresholds by 30% to 50% in order to detect a treatment effect? How did they know that the treatments had not reached the Protocol thresholds that they had so authoritatively defined?