The 2026 ACX/Metaculus prediction contest is now open with a $10,000 prize pool, featuring reader-submitted questions, and Scott announces the winners of the best question submission contest. Longer summary

Scott announces the 2026 ACX/Metaculus prediction contest is live, with questions suggested by ACX readers covering US politics, AI, international affairs, and culture. Predictions must be submitted by January 17th to be eligible for the $10,000 prize pool, though participants can continue updating forecasts afterward for site leaderboards. The post also lists the winners of the best question submission contest, with prizes ranging from $150 to $700. Shorter summary

The 2025 ACX/Metaculus Forecasting Contest is now open, featuring 36 questions and a particular focus on comparing forecasting bots with human predictors. Longer summary

Scott Alexander announces the opening of the 2025 ACX/Metaculus Forecasting Contest, although the 2024 results are pending due to complications. He mentions hoping to compare Metaculus with Polymarket but couldn't due to recent events including FBI raids. Scott expresses particular interest in seeing how new forecasting bots will perform against top human forecasters in this year's contest, which includes 36 questions and offers $10,000 in prizes. Shorter summary

Scott Alexander updates readers on Ukraine war predictions, Insight Prediction's challenges, ACX 2022 Prediction Contest results, and various prediction market developments. Longer summary

Scott Alexander provides an update on prediction markets related to the Ukraine war, discusses the situation with Insight Prediction (a prediction market platform), shares data from the ACX 2022 Prediction Contest, and gives brief updates on various prediction-related topics. The post covers changes in probabilities for key Ukraine war outcomes, the challenges faced by Insight Prediction due to the war, analysis of the ACX prediction contest data, and mentions of new prediction market platforms and AI-related predictions. Shorter summary

Scott offers corrections about Polymarket's status and updates on the 2022 prediction contest, including calls for collaboration and ideas. Longer summary

Scott Alexander provides two corrections and updates to previous posts. First, he clarifies that Polymarket is still operational, offering real-money markets outside the US and working on a US-compliant product. Second, he reminds readers about the 2022 prediction contest entry deadline and shares a message from the contest organizers about potential collaborations with prediction markets and ideas for using the contest data. Shorter summary