AllAmericanBreakfast's Shortform

DirectedEvolution

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Metaculus has a 3% chance of the WHO declaring hantavirus a PHEIC in 2026. Polymarket has 8.6 cents on “yes” for WHO declaring it a full-blown pandemic in 2026. Edit: As of today, Polymarket also has a very thinly traded "hantavirus PHEIC by June 30th" market, which is currently at 12% (was 9% until a few minutes ago). This is a 4x higher probability over a 3-4x shorter timespan than Metaculus's PHEIC market. It's going to be fascinating if we start seeing Polymarket gamblers issuing death threats to the WHO for not issuing the declarations they're hoping for.

The comments on Metaculus are primarily sober, thoughtful analysis, including by individuals like Peter Wildeford. The comments on Polymarket are deeply idiotic gibberish.

All that’s needed for real money markets to underperform is adverse selection on participation.

For an analyst who wants to make money, there‘s abundant, near-zero-friction opportunity in the stock market.

For an analyst who wants to participate in a prediction market on Hantavirus risk, Metaculus is again a zero friction opportunity. There’s little participation by idiotic gamblers, so you primarily encounter other thoughtful analysis in the comments.

For an unusual species of crypto-enthusiast gambler, Polymarket offers a place to get the thrill of gambling on specific world events. For others, it’s a uniquely unattractive mix of low liquidity, limited selection, unregulated, high fraud risk, high friction, rudeness, cultural controversy, and for some, intrinsic badness due to reflexivity (the way it directly incentivizes participants to force bad outcomes in order to win bets).

Given that the whole premise of prediction markets is as a forecast aggregating tool, the entire question of their epistemic utility comes down to whether they succeed in attracting accurate forecasts. If real money markets attract worse forecasts than play money forecast aggregators on net due to adverse selection, they’ll underperform. GIGO.

https://www.metaculus.com/questions/43468/hantavirus-pheic-before-2027/

https://polymarket.com/event/hantavirus-pandemic-in-2026

https://polymarket.com/event/hantavirus-outbreak-by-june-30

4DirectedEvolution5mo

But that’s the empirical question, right? Is trading volume on prediction markets dominated by thoughtful traders or gamblers? It only takes one thoughtless gambler with a large bankroll to outweigh a bunch of high signal traders. Or a bunch of low signal traders with a collectively large bankroll to outweigh a high signal trader. Based on what I see in the comments on the two sites, Metaculus is clearly higher signal regarding hantavirus. And thats quite counterintuitive if you expect polymarket’s got lots of thoughtful traders involved. Shouldn‘t the comments on Polymarket be full of persuasive arguments by traders trying to convince others to come around to their position and increase the values of the shares they own? Why do we see this only on Metaculus, where the only reward is internet points?

4Austin Chen5mo

yes -- but one of the nice fundamental properties of prediction markets is that over time, thoughtful people accumulate larger bankrolls and yes, I think Metaculus comments are generally quite good; Manifold's are sometimes good, Polymarket/Kalshi are approximately garbage. This is I think partly cultural effects (and product decisions) about who comments vs trades and how those get represented, but yes also reflects something important about the distribution of the underlying audience -- that Metaculus has a handful of extremely thoughtful forecasters, polymarket may have that plus a thousand degen gamblers. my contention again is that the structure of markets happily means that the latter can still be quite accurate. I don't know if you've seen https://brier.fyi/ (and, imo their results should be taken with a grain of salt, though also I might just be salty); but my main takeaway is that they're all pretty calibrated, and broadly could be cited much more (whether market or poll)

yes -- but one of the nice fundamental properties of prediction markets is that over time, thoughtful people accumulate larger bankrolls

It's true that superforecasters outperform on forecasting in general. But there are several major issues with the assumption that their increased bankroll can be relied upon to improve the signal. However:

Superforecasters are a small population with a finite amount of time and capital. The number of questions and overall volume on prediction markets may easily grow faster than the number of superforecasters and their bankr

... (read more)