Well yes, in principle of course I agree. And I think that's really true for a treatment. I did think people might disagree with me saying objective outcomes might not be absolutely required in this particular case - but I'm going to try to defend it.I'd require measures of both activity patterns and PEM. We must get away from allowing self-report measures on their own.
The question of whether information about pacing reduces PEM and the question about what is the cheapest and most preferred method of giving information about pacing are two different things. Both are worthwhile questions to answer, but they don't necessarily have to be answered together.
NICE assumed that providing information about pacing was a good thing, so, at least in England, health care workers should be providing information to newly diagnosed people. Is psychotherapy a cheaper and more preferred way of giving people information about pacing than an informed nurse giving someone a talk, a pamphlet and a help-line phone number, or group support sessions? Knowing about whether people with ME/CFS think they feel more confident about managing their illness after being given information is useful and meaningful. Sometimes self-report measures and intervention costs are enough.
When people are first diagnosed (which is when they need the information most), there will be lots of reasons why they can't immediately reduce activity levels and why they still get PEM. If they decide to give up work, there will still be things to sort out. If they decide to move to a smaller house or move home to parents, that will take effort to do. It will take effort to work out childcare options. They will probably still be going to specialist appointments and for tests. I doubt that any measure of activity levels or PEM at the early time would show much difference between the different options over any length of time that is likely to be applied. I think the main thing at that early time is ensuring the person feels that they have the knowledge to manage things.
Maybe what you could do is come back to people a year after their diagnosis and ask them, with hindsight, whether the early support they received was useful. And you could do the assessment of PEM and activity levels then?