[tripletao]

He published a serosurvey that claimed to have found a signal in a positivity rate that was within the 95% CI of the false-positive rate of the test (and thus indistinguishable from zero to within the usual p < 5%). He wasn't necessarily wrong in all his conclusions, but neither were the other researchers that he rightly criticized for their own statistical gymnastics earlier.

https://statmodeling.stat.columbia.edu/2020/04/19/fatal-flaw...

That said, I'd put both his serosurvey and the conduct he criticized in "Most Published Research Findings Are False" in a different category from the management science paper discussed here. Those seem mostly explainable by good-faith wishful thinking and motivated reasoning to me, while that paper seems hard to explain except as a knowing fraud.

[zahlman]

> He wasn't necessarily wrong in all his conclusions, but neither were the other researchers that he rightly criticized for their own statistical gymnastics earlier.

In hindsight, I can't see any plausible argument for an IFR actually anywhere near 1%. So how were the other researchers "not necessarily wrong"? Perhaps their results were justified by the evidence available at the time, but that still doesn't validate the conclusion.

[tripletao]

I mean that in the context of "Most Published Research Findings Are False", he criticized work (unrelated to COVID, since that didn't exist yet) that used incorrect statistical methods even if its final conclusions happened to be correct. He was right to do so, just as Gelman was right to criticize his serosurvey--it's nice when you get the right answer by luck, but that doesn't help you or anyone else get the right answer next time.

It's also hard to determine whether that serosurvey (or any other study) got the right answer. The IFR is typically observed to decrease over the course of a pandemic. For example, the IFR for COVID is much lower now than in 2020 even among unvaccinated patients, since they almost certainly acquired natural immunity in prior infections. So high-quality later surveys showing lower IFR don't say much about the IFR back in 2020.

[mike_hearn]

Yeah I remember reading that article at the time. Agree they're in different categories. I think Gellman's summary wasn't really supportable. It's far too harsh - he's demanding an apology because the data set used for measuring test accuracy wasn't large enough to rule out the possibility that there were no COVID cases in the entire sample, and he doesn't personally think some explanations were clear enough. But this argument relies heavily on a worst case assumption about the FP rate of the test, one which is ruled out by prior evidence (we know there were indeed people infected with SARS-CoV-2 in that region in that time).

There's the other angle of selective outrage. The case for lockdowns was being promoted based on, amongst other things, the idea that PCR tests have a false positive rate of exactly zero, always, under all conditions. This belief is nonsense although I've encountered wet lab researchers who believe it - apparently this is how they are trained. In one case I argued with the researcher for a bit and discovered he didn't know what Ct threshold COVID labs were using; after I told him he went white and admitted that it was far too high, and that he hadn't known they were doing that.

Gellman's demands for an apology seem very different in this light. Ioannidis et al not only took test FP rates into account in their calculations but directly measured them to cross-check the manufacturer's claims. Nearly every other COVID paper I read simply assumed FPs don't exist at all, or used bizarre circular reasoning like "we know this test has an FP rate of zero because it detects every case perfectly when we define a case as a positive test result". I wrote about it at the time because this problem was so prevalent:

https://medium.com/mike-hearn/pseudo-epidemics-part-ii-61cb0...

I think Gellman realized after the fact that he was being over the top in his assessment because the article has been amended since with numerous "P.S." paragraphs which walk back some of his own rhetoric. He's not a bad writer but in this case I think the overwhelming peer pressure inside academia to conform to the public health narratives got to even him. If the cost of pointing out problems in your field is that every paper you write has to be considered perfect by every possible critic from that point on, it's just another way to stop people flagging problems.

[tripletao]

Ioannidis corrected for false positives with a point estimate rather than the confidence interval. That's better than not correcting, but not defensible when that's the biggest source of statistical uncertainty in the whole calculation. Obviously true zero can be excluded by other information (people had already tested positive by PCR), but if we want p < 5% in any meaningful sense then his serosurvey provided no new information. I think it was still an interesting and publishable result, but the correct interpretation is something like Figure 1 from Gelman's

https://sites.stat.columbia.edu/gelman/research/unpublished/...

I don't think Gelman walked anything back in his P.S. paragraphs. The only part I see that could be mistaken for that is his statement that "'not statistically significant' is not the same thing as 'no effect'", but that's trivially obvious to anyone with training in statistics. I read that as a clarification for people without that background.

We'd already discussed PCR specificity ad nauseam, at

https://news.ycombinator.com/item?id=36714034

These test accuracies mattered a lot while trying to forecast the pandemic, but in retrospect one can simply look at the excess mortality, no tests required. So it's odd to still be arguing about that after all the overrun hospitals, morgues, etc.