I'd like to start giving people the option of commenting on shorter Cold Takes pieces (which I don't cross-post here or provide audio for). I'm going to use this post for that: I will generally leave a comment for each piece, and people can leave their comments as replies to that.
Bet with Zvi about Omicron:
I'm definitely on Holden's side of the bet.
In summary, I assign 80% to Holden's outcome, 15% to the ambiguous "push" outcome, and 5% to Zvi's outcome.
This is a low-information forecast, but there seem to be three outcomes to the bet, and Zvi's outcome clearly seems to be the least likely:
(1) For Zvi to win, Covid cases (of all variants, including any future ones) need to average ~18 times higher over the first two months of 2022 than over the following 12 months (math: 18 = (0.75/2) / (0.25/12)).
18 is such a high ratio given Covid's track record so far. The ratio of the 7-day-average of US cases from its high (1/11/2021 = ~256,000/day) to its low (6/21/2021 = ~12,000/day) is ~21, barely higher than ~18. Plus, those two weeks were months apart, giving time for cases to drop off.
I don't see a very plausible way to get that kind of ratio for the first two months of 2022 over the 12 months afterwards. E.g. It seems unlikely that cases would drop off sufficiently quickly at the end of February to avoid adding a large number of cases in March (and to a lesser degree, April, etc). (i.e. Even if cases virtually disappeared later in 2022 (such that the second period being 12 months instead of 6 doesn't matter much), it's really hard for cases to drop off so quickly that the number of cases from March 1 onwards don't end up being at least a third of the number of cases from January and February.) The prior on that steep drop-off happening by the end of February is quite low and the fact that it's only a little over a week until January and cases are still on the rise doesn't make it seem more likely that there will be a steep drop-off before March. There's just no way Zvi could know that that is likely going to happen. I don't need to read his post to know that he doesn't know that.
Given this simple consideration that cases would have to drop off exceptionally fast at just the right time for Zvi's outcome to happen, I assign a 5% chance to Zvi's outcome happening.
It was really just strongly disagreeing that Zvi's outcome seemed likely that made me want to write this comment, but I'll go ahead and write estimates for the other two outcomes:
(2) For Holden to win, cases in the 12-month period after February 2022 have to exceed one-third of cases in the first two months of 2022 before a new variant comes along and takes over. I haven't heard of any new variant after Omicron. Such a new variant would have to be much more contagious than Omicron for it to have a chance to take over everywhere in the US in time to stop Omicron's cases from exceeding that one-third threshold in March-May. I hear Omicron is super contagious so that seems unlikely. Therefore, my low-information forecast is that Holden's outcome is 80% likely.
(3) For the bet to be a "push" (i.e. for the bet to resolve ambiguously), a new variant or variants need to take over before Omicron-and-previous-variant cases after March 1 exceed the one-third threshold mentioned above. This seems more likely than Zvi's outcome, but still not that likely. I'll assign 15% to the ambiguous outcome.