[ncallaway]

> which I believe to be factual, not merely humorous

“Factual” and “humorous” aren’t opposites. I think “publishing in Nature is a strong signal that the results are wrong” is likely to be determined to be an opinion, regardless of whether you mean it serious or as a joke.

The basic dividing line the court has drawn between “factual claim” and “protected opinion” is whether the claim is objective and can be proven true or false.

In general it seems (to me, a non lawyer) that your signal claim isn’t an objective one. There’s no hard line about when a journal would be a “strong signal” vs a “weak signal” vs “no signal” about something being wrong. It’s not really a statement that can be proven to be true or proven to be false. Which is why I think it would be considered to be your opinion about Nature (even if a very serious opinion)