I don't have a rival probability estimate but 2000:1 seems off to me.

@Mauro are you saying that you think 1 in 2000 cases might be malicious, or that there's a 1 in 2000 chance that any case is malicious?

What I said is I estimate the odds are at least a 1:2000 that the cases are 'malicious' (sonic/microwave weapon) vs. being non-malicious (caused by Mass Psychogenic Illness). In other words: should I being offered a bet on 'malicious' or 'non-malicious' I'd bet 'non-malicious', even at 2000:1 (that is to say: up to betting 20$ against a payoff of 1 cent. If the truth is 'malicious' I lose my 20$, if the truith is 'non-malicious' I end up with 20.01$ ).

My initial guess would be something like: 90% confidence that >90% of reports have non-malicious causes. Of the remaining 10%, I don't have a sense of how to assign probabilities.

Then you should at most accept a bet at 9:1 (let's assume the remaining 10% cases are in fact malicious): at most 9 cents, with a payoff, in case you win, of 1 cent (as in the previous example).

As

@Mendel is always very fond to remind us, I'm "not assigning probabilities, just making up numbers", which is mildly annoying to hear, but which introduces the second part of my answer to

@Bird. 'Initial guesses' are not bad at all, however they can often be improved. This is why I just avoided to

*only* 'make up numbers', instead I showed Mass Psychogenic Illness has a prior probability of existing of about ~100%, while "sonic/microwave weapons which can do harm at distance

*while at the same time being undetectable" *surely have a much lower probability than that. My 1:1000 probability estimate

*is *a made-up number, of course

*,* but everybody is free to make up its own number and then use it the same way I did. It's the

*method which matters*, not the exact numbers one puts in, and

*the conclusion is always the same*: Mass Psychogenic Illness has a higher prior probability than "sonic/microwave weapons which can do harm at distance while at the same time being undetectable

*"*.

The second division by 2 is a given: every time an additional hypothesis is added, and we have no idea if the hypothesis is true or false, it could be 50% true or 50% false, so we need to halve the probabilities (or double the odds). You can think of this as Occam's razor put in a mathematical form. Then of course, should we know anything about the effects of "sonic/microwave weapons which can do harm at distance while at the same time being undetectable

*", *this factor could be refined, in a sens or in the other (but we don't even know if those weapons can possibly exist, it's hard to know something about their effects)

*.*
Just to reiterate! The most important thing is the

*method* one uses to try to sort true from false: compare (I stress it: compare!) the odds of two different hypothesis, starting from the prior odds and then adding in the evidence, which means: how much well the 1st hypothesis explains the evidence, compared to the 2nd hypothesis? The exact numbers itself do not matter much, put in yours (honestly) and make your own estimations.

And now I have a question for

@Mendel: honestly, how many $ would you dare to bet on Havana Syndrome being caused by Mass Psychogenic Illness vs. sonic/microwaves weapons, with the bet paying 1 cent if Mass Psychogenic Illness is the true answer (you lose your $ if the true answer is 'weapons', you gain 1 cent + your dollars back if the true answer is 'Mass Psychogenic")?