128 Comments

The "fortified essays" seem quite interesting, and reading the description, it doesn't seem like it's a full-time job, so maybe I'll do it on the side. I could imagine writing things in the style of "X: much more than you wanted to know"

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I’m writing to lodge a minor objection to the title of this series. I find it hard to believe I’m the only one who, every time one of these comes in, finds himself stuck with that horrible Bangles song from the 1980s stuck in my head for the rest of the day. (“Just another man[t]ic Monday.”)

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The 9-12% range of estimate is a pretty large uncertainty for the baseline, 24% could be double or almost 3x.

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Did you have to give an SSN for Kalshi? I know it's regulated, but that still bothers me a little.

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Why should Kalshi be less than 10% on their fees? That’s what a typical sports book would be charging, and their motivations (i.e. profit) are the same. I guess a few online sports books go cheaper, but they have more competition. Frankly I’m surprised Kalshi’s fees are that low if they’re the first regulated company into this market.

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I notice there are no predictions about vaccine breakthrough, though I see there's one about variants.

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"percent of Americans who die of COVID between now and 1/1/22 who were fully vaccinated" is ambiguous, and I first read it as "X% of the set of Americans will have been vaccinated and also die from COVID" rather than "out of the set of Americans who die of COVID, X% will have been vaccinated". Thus my WTF reaction to your estimate of 2.5%.

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Is there any long-term prediction markets covering ambiguous questions in the realm of science? I'd be particularly interested in what they would predict the field of nutrition science will say about e.g. what is the healthiest way to eat in 10, 20, 30 years. Will they have settled on low-carb? Back to low-fat? Etc.

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founding

China dependency ratio - I guess that China will raise the retirement age and that will slow the growth of the dependency ratio

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Scott, where did you get the 10% number from for the Kalshi fees? The document you linked shows the largest fee as $0.0175 for $0.50 of profit, so isn't that 3.5%?

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So I'm trying to see what markets are on Kalshi but I can't find a page for it (without signing up, anyway -- I just want to see all the markets, I don't want to actually sign up). Is there a way to see this? I can find pages for individual markets, but not for the overall list of markets. (It isn't https://kalshi.com/markets/ ; that doesn't work.)

One ought to be able to see the list of markets without signing up!

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Am I misunderstanding or are the fees for Kalshi quite a bit less than 10%?

It looks like for 1-cent contracts the fee is 7%, but it looks like it is lower than that for higher-cost contracts - e.g. the fee for one hundred 50-cent contracts is $1.75, which is only 3.5%.

And for one hundred 99-cent contracts, the fee is 7 cents, which is less than 0.1%.

So on average the fee is around 3.5%? I might be misunderstanding the fee schedule though.

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I've been trading on Polymarket for two months, and it's been incredible. I am learning a lot more on the subjects I am wagering on, and it is still vastly inefficient. I have seen some people do very little work to guarantee themselves 5 figure payouts. This is what trading bonds in the 80s much have felt like to an extent.

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All these prediction markets, and not a single one where I can bet on who the final Smash character will be. :P

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I had not heard of dependency ratios before, and I was VERY surprised at those numbers until I looked "dependency ratio" up on Wikipedia and discovered that it is conventionally multiplied by 100 (i.e. expressed as a percentage). So a dependency ratio of "50" means 0.5 dependents per working-age person, not 50 dependents per working-age person.

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Polymarket and Metaculus have a gap between them for 100k COVID cases before 2022 (95% vs 85%). Does that mean you could bet them against each other for a guaranteed payoff? If you can't, does that indicate a deficiency in their payoff algorithm? Or goes the gap persist because of fees or some other impediment?

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founding

> check a box saying you read some long contracts which you realistically did not read

Note that Kalshi's various agreements are not entirely screwing around. In particular, there are specific prohibitions on "participating in a contract if you ... have material non-public information regarding this contract, or ... have the ability to influence the outcome of the contract." I recommend assuming that a violation of this provision will be costly to you, whether or not it gets you in actual legal trouble, and generally treating this more like real securities trading, and less like play money cryptocurrency screwing-around, then one might otherwise be inclined.

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founding

> Right now it’s 50 across most of the world, except in Africa where it’s 80

Perhaps obvious in retrospect, but you might want to clarify that, even though this is called the "dependency ratio", it is in fact measured as a percentage, not really a ratio. I.e. that's 50% and 80% as many dependents as non-dependents.

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Biden at 42 seems really cheap. I wouldn’t take 80 but 42? Anyone have reasons against that? Death tables are .05 probability of death per year at 80ish and that includes, I believe, nursing home vegetables and the like. Also Kamala winning a primary seems questionable.

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Just signal boosting my Twitter account (https://twitter.com/metaculusextras) which shares the best comments and predictions from Metaculus each week

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Scott you better apply for (contributing to) that ‘fortified essay’ stuff!

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Listing the prediction about "Haredi" population in Israel together with the estimates of total dependency makes a lot of sense, as this population is typically dependent: many of the Haredi men do not work or work in low paying teaching jobs.

The current level of dependency is barely sustainable; It's hard to imagine the current system persevering with 24% of the population.

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Can prediction markets not change how prices map to probabilities to address the issue of fees skewing the prediction? Or is the concern more than fees drive down volume?

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Thanks so much for banging on this drum. I had my own ideas for a while on 'how the fuck do you solve the problem of news being largely narrative nonsense', but the only solution i could think of was too complicated and seemed like it was ideal for a race of dispassionate computer-beings.

Prediction markets are much more plausibly a path out of 'the common knowledge is a mixture of data-driven accuracy, and bs promoted by the modern equivalent of priests enforcing an orthodoxy'.

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"Once everyone has been vaccinated or infected, it settles down into something about twice as bad as the flu."

I was surprised to read this. Partly because I don't think in the 2022-5 period everybody who is going to get infected will have already done so. But even allowing for that, it seems high - I was under the impression that in a population where most people (and very nearly all of the vulnerable) have been vaccinated, Covid will kill less people than flu rather than twice as many.

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"I think for the percent question I would guess something like 2.5% for this - right now it’s 1%"

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According to the official UK data, fully vaccinated make up 54% of all deaths from delta. Israel’s data suggests a comparable ratio (though the sample size is still small).

According to Fauci, the vaccinated make up 0.8% of all recent deaths.

If you had to make a prediction - what is the probability that Fauci’s statement is true or close (say, up to a factor of 3) to reality?

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> Dependency ratio is the ratio of non-working age people (eg elders, children) to working-age adults. Higher numbers mean more dependent people and greater economic burden. Right now it’s 50 across most of the world, except in Africa where it’s 80 (Africa has lots of kids!).

Nitpick: Assuming all of the dependants are kids, this means around 100 children per couple, which seems a bit high for a K-selected species? Realistically, I think there are some percentage signs missing here, e.g. the dependency ratio is really 0.5?

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I have to admit I’d love to be an Analytical Storyteller, except that I’m functionally innumerate and shouldn’t be participating in prediction markets in any sense. But if someone fed me the numbers I’d love to do this kind of writing.

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It'd be interesting to see if there are any arbitrage opportunities. Though these markets are probably too small and the population participating is too variable to develop reliable predictions about how poor prediction markets are at making predictions - that was a fun sentence. But if they consistently over or under estimate certain categories of topics, then one could make bets without really knowing anything about the question area.

I suppose part of the market element is to attract such arbitrage focused traders whose bets would then balance out the ratios....but with any low volume market, one could make significant money by 'providing' such services. Even a small 5-10% advantage would be great if one could find a consistent trend to under/over estimate health outcomes or narrow/broad topics of single states vs whole nations, etc.

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I'm surprised and disappointed that "reddit predictions" isn't the thing I imagined when I heard that: Use a karmic prediction market to set initial scores on posts. This would actually solve a massive ongoing problem with reddit:

New posts rise or fall according to the whims of a very small sample of atypical voters. They can easily be sunk for stupid reasons that most members of the sub wouldn't agree with. Using a prediction market to set scores instead wouldn't have this problem.

Bettors would be answering a question like "what will the up/down ratio of this be once 150 total votes have been cast". Until the post reaches 150 votes, the post would be ranked according to their prediction instead than the actual vote ratio, which for the above reasons, at that stage, is too volitile to be used. Once it reaches 150 votes, the bettors receive their predictionkarma payouts and it's ranked according to the actual ratio from then on.

(note, reddit doesn't actually use vote ratio (`up/(up+down)`), it uses `up - down`. I've never come across a justification of this, it seems like that would amplify "oldest post wins" effects, so I wont advocate it, but if they'd prefer to keep that, the betting question could be adapted to "what will the score be after a day's viewing". Personally, that seems like a much more annoying question, because it's confounding itself with the number of people who happen to come online that day, which I'm going to be much less interested in learning to predict, the online system shouldn't really care about that.)

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