Hmm,... Are you sure? As I remember it, he chose not to be on the panel out of respect for all the patients and advocates who protested against the panel and urged them to accept CCC instead of creating something new. He has commented openly on this, I can't remember where though (article, on his blog, on his Facebook page?).
I don't think it's fair to call him "hostile"...
ETA: "To Serve or Not to Serve: Ethical and Policy Implications" Leonard A. Jason
https://onlinelibrary.wiley.com/doi/pdf/10.1002/ajcp.12181
"The IOM solicited opinions from many patients as well as scientists, and I was invited to address the IOM in the spring regarding case definition issues."
https://blog.oup.com/2015/02/disease-name-chronic-fatigue-syndrome-me/
Ah, so he was invited to join and declined. That makes sense. I was wrong about that bit. As for his justification...? Hmmm. I'm not sure.
Why did he decline to engage at every step if he knew this was going to be a major report with international clout? Why does he still not give us a better solution?
He signed a letter he had several problems with but wouldn't even deign to review the IOM proposals because it would put his name on it? I don't buy that.
He makes a big deal of his IOM criteria study, but equally found increased rates of psychiatric illness in the CCC and ICC criteria over the years too. He's being disingenuous if he ignores his own studies to hammer home the problems with IOM. As Cinders66 says, he's not really offering any better ideas, either.
The obvious suggestion is that it may not be any of those criteria that's at fault, but rather his shaky interpretation of PEM. Bad studies on criteria are as problematic as bad studies into GET, even if they reaffirm what we want to hear.
He's apparently recognised the problems with how he defined PEM now, which is why he's trying to come up with a new way to accurately capture it. I wonder if this would change the findings using the IOM criteria?
Let's set aside the name (I hate SEID as a name, but it's less offensive than CFS). Let's focus on what we know: PEM/PENE is ostensibly the single defining feature of ME. If this is true, then a criteria that helps us properly define PEM/PENE should be all we need to properly diagnose ME. The rest helps build a clinical picture but isn't essential.
IOM does require PEM, so the question is: how good is it at defining PEM? I'm not sure the criteria themselves are very good at explaining PEM, although the attached report (Beyond ME/CFS...) does a much better job and goes further to label ME a specific 'disease', rather than a syndrome, defined by that trait.
Taken together, they're far from perfect, but I think they've made a bigger impact on changing the US guidelines--and international perception of ME--than any of the other guidelines ever did. Lots of newspapers ran with the 'ME is real and it's physical' thing after the IOM report, which was really valuable, even if annoying in many ways.
Jason could have done much more inside and as part of the process, than outside. Many of the people who wrote the CCC and ICC were involved in the IOM report too. I think they cared about getting the best solution, too, but were required by their brief to find a new name.
tl;dr: Yes, Jason has found problems with IOM, but he found similar problems with CCC and ICC. I don't think we can consider him 100% reliable on this issue.
