Zvi Mowshowitz and I have agreed to the following bet:

• If at least 75% of the USA COVID-19 cases between 1/1/22 and 2/28/23 (inclusive) occur between 1/1/22 and 2/28/22 (inclusive), I pay Zvi $40.
• Otherwise, Zvi pays me $60.
• This bet is intended to apply to Omicron and earlier strains, and it will be a “push” if a post-Omicron strain “muddies the waters” in the following sense: counting cases from the new strain would cause me to win, and not counting them would cause Zvi to win.
• We'll use Wikipedia for total COVID-19 cases and this CDC data for variant information. Each of us has the option to appeal to a third party (whom we've agreed on) to perform an adjustment for undertesting.

The concept this is trying to capture is that Zvi thinks there’s a 70% chance of the following: “Omicron will blow through the US by 3/1/2022, leading to herd immunity and something like the ‘end’ of the COVID-19 pandemic.” I think there’s only a 50% chance of this (and I would’ve had a lower probability before learning that Zvi thinks it). We bet at 60%.

I think the most important takeaway for readers is that Zvi thinks Omicron is going to blow through the US very soon and very quickly. If you think this is likely to end up being true, I think that makes this a good time to be extra cautious, as it implies that the next ~2.5 months are much more dangerous than any time afterward. (Zvi: "The flip side is that if you can't avoid it at all, you might not want to bother trying.")

Now a bit more info on how this bet came about and what’s going on here:

• In response to my Dec. 6 post on Omicron boosters, Zvi (over email) expressed skepticism that Omicron boosters are a good thing to push for, compared to e.g. faster approval for and production scaling of Paxlovid. His take was that even if they were approved immediately, there was no chance to roll them out in time to get ahead of what he sees as the likely “last wave” of COVID-19.
• I had a reaction along the lines of: “I’ve heard a bunch of times before that we’re about to see a huge wave of COVID-19, followed by herd immunity and the end of the crisis. It seems to me that simple epidemiological models tend to point toward this kind of prediction. But it hasn’t happened before, and I don’t think it’ll happen this time either. Something else seems to happen when incidence reaches a certain level - maybe it’s behavior change, maybe it’s something to do with the fact that there are lots of subpopulations that mostly interact with each other, I don’t know - but these models seem off, and I wouldn't be confident that the next couple months will be the big and final wave.” So I offered a bet on this specific point, which we then spent a few emails formalizing.
• Zvi’s response to this argument: "yes, the reason to doubt this will happen is that it kept not happening in the past, but the dynamics pointing in this direction are much stronger this time, and it would be very difficult to overcome them with changed behaviors - it’s too tall a hill, and we’re not in any shape to climb it." (I think this argument is persuasive, but not persuasive enough to get me to Zvi's position.)
• (I no longer think there’s any chance that Omicron-specific boosters will get approved anytime soon, in light of evidence that has since come out about the protective effects of normal boosters and comments from public officials. I still think they should have been approved by now though!)

In many ways this is a completely insane bet for me to make:

• Zvi has been thinking and writing a massive amount about COVID-19, and his work has been high-quality in my view.
• I have spent some time thinking about COVID-19, but much less, and I’ve generally been somewhat lazy about this bet. For example, when Zvi sent me the Google Sheet he was using to model the situation, I wrote back: “I glanced at your sheet but couldn't easily follow it … But I sort of did see the main thing I want to bet against, which is the fact that you copied the same formula all the way down the key column.”
• Zvi also spends most of his professional time working in some capacity with betting markets!
• Zvi is aware of my argument.

So, as a reader you might just want to assume Zvi is right and act accordingly.

But I find I can’t shake my view that the probability he’s giving is too high, and I’ve decided to put my money where my mouth is, and I thought readers would be interested in the whole phenomenon. Fun exercise: which side of this bet would you want to be on?

A couple more notes

The bet is not for a life-changing amount of money. There's simply no way that this sort of activity is an optimal way for either of us to work toward personal financial goals. That's not why we're betting; we're doing it more as a sort of "holding ourselves accountable for our beliefs" sort of thing.

In an ideal world, we'd be making so many bets like this that our track records would give clear evidence of which of us was a better predictor, overall. But I don't think that's going to happen; it's a lot of work even to nail down a pretty simple, vivid disagreement like this one (and most important disagreements are much harder to reach bets on, and even this one may require a third-party judgment-driven adjustment). I don't think that whichever of us wins this one bet should gain too much credibility relative to the other.

So if winning/losing this bet won't have a significant effect on my finances or on my credibility, what's the point? Honestly, I don't totally know. I have an intuition that when I notice a disagreement this crisp and clear with someone, it's cool and good for our epistemic habits to try to nail it down, define it, record it, and ultimately feel some consequences for how it turns out (certainly I care whether I win, despite the two points above)!

You could think of it as taking opportunities where I see them to try out living in the world of the Bayesian mindset.

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