Predict 0.1%—99.9% With Decimal Forecasting
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Decimal Forecasting ------------------- Forecasters have long sought the ability to predict low-probability events below the 1% threshold. We're excited to introduce a new capability that enables just that. Decimal forecasting means you can predict probabilities as high as 99.9%, as low as 0.1%, and every tenth of a percent in between.  How Does It Work? ----------------- On desktop, hover over the prediction slider to reveal arrows. Click one to adjust your forecast by 0.1%. (On mobile, the arrows are always visible.) Dragging the slider only selects between integer probabilities, just like before. Watch Your Score: Tail Risks ---------------------------- With great precision comes great responsibility. While the math behind [Brier](https://www.metaculus.com/help/faq/#brier), [log](https://www.metaculus.com/help/faq/#log_score), and [tournament](https://www.metaculus.com/help/faq/#tournament-scoring) scoring has not changed, incorrect 99.9% and 0.1% predictions result in significantly worse log and tournament scores relative to 99% and 1% predictions, whereas correct predictions score only slightly better. [Scoring remains proper](https://www.metaculus.com/help/faq/#fewpoints), so predicting your true beliefs is still the best strategy. If the true probability is 0.1%, you will maximize your score over many questions by predicting 0.1%. Make Some Finer Forecasts ------------------------- Here are a few questions where more precision could be useful: - [Will Life Be Discovered on Venus before 2035?](https://www.metaculus.com/questions/5255/life-on-venus/) - [Will There Be a Nuclear Detonation in Ukraine by 2024?](https://www.metaculus.com/questions/13171/nuclear-detonation-in-ukraine-by-2024/) - [Does P = NP?](https://www.metaculus.com/questions/1408/p--np-is-true/) - [Will AI Be Able to Read a Novel Before 2030?](https://www.metaculus.com/questions/11177/ai-book-comprehension-before-2030/) - [Will Cosmologists Favor Universe Acceleration?](https://www.metaculus.com/questions/3608/will-the-majority-of-leading-cosmologists-in-2030-agree-that-the-evidence-points-to-an-accelerating-universe/) All Decimal Systems Go ------------------------- Decimal forecasting is valuable on its own, and it's also a step toward additional exciting improvements. We're always keen to hear your opinions and ideas — please share your feedback on decimal forecasting in the comments below, and tell us what else you'd like to see in the future!