Peter White in 2000 on subjective (SF-36 PF) vs objective measures Just been reading a paper looking at the exercise capacity of CFS patients, which I will post on later. But for now I was struck by the authors' comments on the value of objective over subjective measures: Strength and physiological response to exercise in patients with chronic fatigue syndrome. 2000. Kathy Y Fulcher, Peter D White Talking about the SF-36 Physical Function scores. (my italics): Talking about the results of their GET programme: You might have thought that would lead Peter White to not rely solely on subjective measures as the primary outcome of PACE. @Dolphin: I think there is a general problem inusing questionnaires, tests (or even actometers)that no one really measures their ability to accurately measure small changes. The only such testing I've come across looks at changes in the test/score correlated with eg hip replacement surgery, where a large change is expected.