Latest discussion here: https://www.s4me.info/threads/the-d...-validation-study-2019-sunnquist-et-al.11289/. It's a fine questionnaire and much better than any of the others but it's still missing a lot of the weirdness and fluctuation, something that can only come from the input of many patients. It's far too easy to anchor on our own experience so requires a broader approach. The sheer number of symptoms makes it hard to select for those that are relevant. Typically such questionnaires will focus on the most common symptoms but there is such a wide range that it becomes a kind of situation like "rare diseases may be rare but there are many rare diseases and added up they aren't quite as rare". Patterns of symptoms are also central to the illness and that's hard to reflect without asking for a deluge of data from the patients.