Oracle Arena
A private prediction tournament for a small group of friends, scored by the methods of the Good Judgment Project.
What we're measuring
The Brier score
Every prediction is a probability between 0 and 100%. When the question resolves, we measure how far you were from the truth — squared.
QuestionWill the Lakers make the playoffs?Your probability0.62Outcome1 (yes)Brier score(0.62 − 1)² = 0.144
Lower is better. 0 is perfect.
Two scores
Gut and Updated
Gut Brier
Your first instinct, frozen at lock-in. Rewards the call you'd make with no time to think it over.
Updated Brier
The time-weighted average of every probability you held as the question played out. Rewards good Bayesian updating.
How a round works
- 1ProposeAny member writes a question — binary, multi-choice, or numeric.
- 2Co-signAnother member affirms the question. One co-sign makes it eligible.
- 3LockOn round day, the group reviews and locks the question set.
- 4PredictWithin 24 hours of lock, every member submits their gut call.
- 5UpdateRevise as news comes in. Every change is timestamped.
- 6ResolveOn the resolution date, the named resolver records the outcome.
- 7DisputeAnyone may dispute a resolution for 48 hours. Group vote decides.
The leaderboard
An archive of who saw what coming
| # | Member | Updated | Gut |
|---|---|---|---|
| — | Member A | 0.181 | 0.197 |
| — | Member B | 0.213 | 0.224 |
| — | Member C | 0.241 | 0.252 |
Members anonymised until you enter.
Methodology