The original study found their technique to have a superior brier score compared to a prediction market (https://goodjudgment.io/docs/Goldstein-et-al-2015.pdf h

The original study found their technique to have a superior brier score compared to a prediction market (https://goodjudgment.io/docs/Goldstein-et-al-2015.pdf https://goodjudgment.io/docs/Goldstein-et-al-2015.pdf). Metaculus also employs a similar technique. It's been a while since I've read it, but the book (Superforcasting) also had an additional section elaborating on a comparison against prediction markets. From memory, the core thesis of the GJP is that some individuals are good at making forecasts, and this accuracy is not domain specific or require insider information. Once measured, more weight is put onto those who make better opinions. As an analogy consider asking 100 chess players for the next move in a game - those with a higher elo are more likely to find a better next move. Conventional prediction market doesn't have this kind of "long term weighting", instead relying on individuals to bet according to their confidence (which may not always correspond to their accuracy). Of interest is this article (https://mikesaintantoine.substack.com/p/scoring-midterm-election-forecasts https://mikesaintantoine.substack.com/p/scoring-midterm-elec...) which compared PredictIt, FiveThirtyEight and Manifold Markets (a prediction market with play money, so in theory no "proper" incentives). Even with the "proper incentives" it did no better Manifol Markets and a decent bit worse than 538.