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What will the community log-score be after the 500th question?
Consider some Metaculus question you know little about. This might be whether the star KIC 9832227 will go "red nova", whether the 2048-bit RSA cryptosystem will be broken before 256-bit Elliptic Curve Cryptography, or whether Piracetam is a more effective Alzheimer's treatment than Memantine. Your guess might be that such a difficult question might well be equally likely to resolve one way as the other.
You can expect the community to do much better. In fact, even though the community predictions are not always perfectly calibrated, you should expect it to predict an approximate average of 63% to those that resolve positively, and 37% to those that resolve negatively . That's how much signal the Metaculus community are able to extract from what might seem like noise. Impressive right?
The Log score is a commonly-used scoring rule, which (relative to the Brier score) gives a larger penalty for being confident (i.e. predicting near 1 or near 99%) but being wrong. Currently (as of 06/11/18), 276 questions have been resolved and the community log score is 0.167. The lower the score, the more precise and well-calibrated the predictions are.
What will the community log-score be after the resolution of the 500th question on Metaculus?
The log-score is computed as follows for a single forecast of probability , if the event occurred, and if not. The scaling is chosen such that it matches the Brier score for a 50% prediction.
 This is a back-of-the-envelope estimate. I assume that the success rates are on average 5% removed from predictions made (imperfect calibration). Then, given a log score of 0.167 you would expect if .
Metaculus help: Predicting
Predictions are the heart of Metaculus. Predicting is how you contribute to the wisdom of the crowd, and how you earn points and build up your personal Metaculus track record.
The basics of predicting are very simple: move the slider to best match the likelihood of the outcome, and click predict. You can predict as often as you want, and you're encouraged to change your mind when new information becomes available. With tachyons you'll even be able to go back in time and backdate your prediction to maximize your points.
The displayed score is split into current points and total points. Current points show how much your prediction is worth now, whereas total points show the combined worth of all of your predictions over the lifetime of the question. The scoring details are available on the FAQ.
Note: this question resolved before its original close time. All of your predictions came after the resolution, so you did not gain (or lose) any points for it.
Note: this question resolved before its original close time. You earned points up until the question resolution, but not afterwards.
This question is not yet open for predictions.
Metaculus help: Community Stats
Use the community stats to get a better sense of the community consensus (or lack thereof) for this question. Sometimes people have wildly different ideas about the likely outcomes, and sometimes people are in close agreement. There are even times when the community seems very certain of uncertainty, like when everyone agrees that event is only 50% likely to happen.
When you make a prediction, check the community stats to see where you land. If your prediction is an outlier, might there be something you're overlooking that others have seen? Or do you have special insight that others are lacking? Either way, it might be a good idea to join the discussion in the comments.