Metaculus FAQ

Basics

Metaculus Questions

Question Resolution

Predictions

Scoring

Forecasting Causes

Tachyons

Miscellany

Basics

What is the aim of Metaculus?

Metaculus poses questions about the occurrence of a variety of future events, on many timescales, to a community of participating predictors — you! Like many mental capabilities, prediction is a talent that persists over time and is a skill that can be developed. By giving steady quantitative feedback and assessment, predictors can improve their skill and accuracy, as well as develop a quantified track record. Then, probabilities of future events can be reliably drawn by optimally aggregating predictions — counting more heavily those with domain expertise and a strong prediction track record.

Some events — such as eclipse timing and well-polled elections, can often be predicted with high resolution, e.g. 99.9% likely or 3% likely. Others — such as the flip of a coin or a close horse-race — cannot be accurately predicted; but their odds still can be. Metaculus aims at both: to provide a central generation and aggregation point for predictions. With these in hand, we believe that individuals, groups, corporations, governments, and humanity as a whole will make better decisions.

As well as being worthwhile, Metaculus aims to be interesting and fun, while allowing participants to hone their prediction prowess and amass a track-record to prove it.

Who created Metaculus?

Metaculus originated with two researcher scientists, Anthony Aguirre and Greg Laughlin. Aguirre, a physicist, is a co-founder of FQXi.org, which catalyzes breakthrough research in fundamental physics, and of Futureoflife.org, which aims to increase the benefit and safety of disruptive technologies like AI. Laughlin, an astrophysicist, is an expert at predictions from the millisecond predictions relevant to high-frequency trading to the ultra-long-term stability of the solar system.

Is Metaculus a prediction market?

Sort of. Like a prediction market, Metaculus aims to aggregate many people's information, expertise, and predictive power into a single high-quality estimation of the probability that something will occur. However, prediction markets as such operate using real or virtual currency, which is used to buy and sell shares in "event occurrence." The idea is that people buy (or sell) shares if they think that the standing prices reflect too low (or high) a probability. Metaculus, in contrast, directly solicits predicted probabilities from its users, then aggregates those probabilities. We believe that this sort of "prediction engine" or "prediction assembler" has both advantages and disadvantages relative to a "prediction market."

Metaculus Questions

What sorts of questions are allowed, and what makes a good question?

Most questions ask the predictor to choose between two mutually exclusive outcomes of future events. Some questions ask the predictor to estimate the date of some future event, or to estimate the quantity of something at a particular date.

They generally take the form "Will (event) X happen by (date) Y?" or "When will (event) X occur?" or "What will the value or quantity of X be by (date) Y?"

A good question will almost certainly be unambiguously resolvable. For example, a committee of people with perfect precognition should be able to definitively agree upon the answer. A good question will also, of course, be interesting!

Questions should also avoid some of the obvious no-nos:

  1. Questions should respect privacy and not address the personal lives of non-public figures.
  2. Questions should not be directly potentially defamatory or generally in bad taste.
  3. Questions should never aim to predict mortality of individual people or even small groups. In cases of public interest (such as court appointees and political figures), the question should be phrased in other more directly relevant terms such as "when will X no longer serve on the court" or "will Y be unable to run for office on date X". When the topic is death (or longevity) itself questions should treat people in aggregate or hypothetically.
  4. More generally, questions should avoid being written in a way that incentivizes illegal or harmful acts — that is, if one were to imagine that the stakes of getting a question correct were high enough to motivate someone to interfere in real-world events to change a question's resolution, those actions should not be by their nature illegal or harmful.

Who creates the questions, and who decides which get posted?

Many questions are launched by Metaculus staff, but any logged-in user can propose a question. Proposed questions will be reviewed by a group of moderators appointed by Metaculus. Moderators will select the best questions submitted, and will (probably) edit the question to add links, background material, remove ambiguity, etc., prior to publishing the question.

How can I get my own question posted?

Below are some guidelines, and then there is also a longer, more comprehensive guide to question writing located here.

  1. If you have a basic idea for a question but don’t have time/energy to work out the details, you’re welcome to submit it; it will go in the queue for potential development and launch by the moderators. (This queue is pretty backlogged, but we do try to prioritize user submissions.)
  2. If you have a pretty fully-formed question, with at least a couple of linked references and fairly careful unambiguous resolution criteria, it’s likely that your question will be reviewed and launched quickly.
  3. Although you can presently just pick one topic for your question, the moderators may well add more.
  4. While formally open to all sorts of questions, Metaculus is currently topically biased toward scientific and technological advances. So suggested questions on other topics, especially that require a lot of moderator effort to get launched, will be given lower priority and may be deferred until a later time.
  5. We regard submitted questions as suggestions and take a free hand in editing them. If you’re worried about having your name on a question that is altered from what you submit, or would like to see the question before it’s launched, please note this in the question itself; questions are hidden from public view until they are given “upcoming” status, and can be posted by "anonymous" or by a moderator upon request.

Note that staff is limited, and there is a backlog of good questions, so if yours has not yet appeared, don't despair!

What can I do if a question I submitted has been pending for a long time?

The turnaround time for most submitted questions is roughly a week. If your question has been pending for significantly longer than that, check to make sure there hasn’t been a comment from staff asking for clarification or suggesting a change. If there hasn’t, you can comment to make sure it’s on the Metaculus team’s radar. You might also tag a team member such as @Anthony, @christian, or @max.wainwright in your message.

What is a discussion question?

Discussion questions are topics of general interest that Metaculus users can comment on, or that represent opportunities for the community to provide feedback to the Metaculus team. A good discussion question should be general enough that it wouldn’t fit well within a prediction question.

What is a private question?

Private questions are questions that other users can't normally see. They aren't subject to the normal review process, so you can create one and predict on it right away. You can resolve your own private questions at any time, but points for private predictions won't be added to your overall Metaculus score and they won't affect your ranking on the leader board.

You can use private questions for anything you want. Use them as practice to calibrate your predictions before playing for points, create a question series on a niche topic, or pose personal questions that only you can resolve. You can even invite other users to view en predict on your own questions!

What are the rules and guidelines for comments and discussions?

Here are some basics:

What do "credible source" and "by [date X]" and such phrases mean exactly?

To reduce ambiguity in an efficient way, here are some definitions that can be used in questions, with a meaning set by this FAQ:

  1. A "credible source" will be taken to be an online or in-print published story from a journalistic source, or information publicly posted on a the website of an organization by that organization making public information pertaining to that organization, or in another source where the preponderance of evidence suggests that the information is correct and that there is no significant controversy surrounding the information or its correctness. It will generally not include unsourced information found in blogs, facebook or twitter postings, or websites of individuals.
  2. The phrase "By [date X] will be taken to mean prior to the first moment at which [date X] would apply, in UTC. For example, "By 2010" will be taken to mean prior to midnight January 1, 2010; "By June 30" would mean prior to midnight (00:00:00) UTC June 30.

Question Resolution

What are the "open time", "close time" and "resolve time?"

Questions must contain an open time, a close time and a resolve time.

The close time must be at least one hour prior to the resolve time, but generally will be much earlier, depending upon the context. Here are some guidelines:

Note: points are steadily awarded between question opening and question closing, with an extra 50% apportioned at the time of question closing. Thus if resolution occurs before closing (as in the third case), less overall points are awarded. This is to prevent gaming of the point system.

Who decides the resolution to a question?

After the closing date, questions are eligible to be resolved. Binary questions can resolve positive, negative or ambiguous. Range questions can resolve to a specific value, or ambiguous. Only Metaculus Administrators can resolve questions. An ambiguous resolution generally implies that there was some inherent ambiguity in the question, that real-world events subverted one of the assumptions of the question, or that there is not a clear consensus as to what in fact occurred.

Some questions take consensus within the Metaculus community as their resolution criterion. At question resolution, a median prediction of <20% (or some other value set by the question writer) would resolve the question negatively, and a median prediction of >20% would resolve it positively. This system is still being tested and most questions will not resolve this way. It is clearly indicated when questions make use of this system.

Do all questions get resolved?

Currently, all questions will be resolved.

What happens if a question gets resolved in the real world prior to the close time?

When resolving a question, the Moderator has an option to change the effective closing time of a question, so that if the question is unambiguously resolved prior to the closing time, the closing time can be changed to a time prior to which the resolution is uncertain.

When a question closes early, the points awarded are only those accumulated up until the (new) closing time. This is necessary in order to keep scoring "proper" (i.e. maximally reward predicting the right probability) and prevent gaming of points, but it does mean that the overall points (positive or negative) may end up being less than expected.

What happens if a question's resolution criteria turn out to have been fulfilled prior to the opening time?

Each question is assumed to have as an implicit assumption that the event it is asking about has not yet occurred as of the time of the question's opening. If it turns out that the event required for a question to resolve as true has already occurred prior to the opening time, so that there has in fact been no uncertainty (but just perhaps obscurity) as to the outcome of the question, then the question will resolve as ambiguous.

What happens if a resolution source is no longer available?

There are times when the intent of a question is to specifically track the actions or statements of specific organizations or people (such as, "how many Electoral Votes will the Democrat win in the 2020 US Presidential Election according to the Electoral College"); at other times, we are interested only in the actual truth, and we accept a resolution source as being an acceptable approximation (such as, "how many COVID-19 deaths will there be in the US in 2021 according to the CDC?"). That said, in many cases it is not clear which is intended.

Ideally, every question would be written with maximally clear language, but some ambiguities are inevitable. Unless specifically indicated otherwise, if a resolution source is judged by Metaculus Admins to be decfunct, obsolete, or inadequate, Admins will make a best effort to replace it with a functional equivalent. Questions can opt-out of this policy with language such as "If [this source] is no longer available, the question will resolve Ambiguously" or "This question tracks publications by [this source], regardless of publications by other sources."

Predictions

How do I make a prediction? Can I change it later?

You make a prediction simply by sliding the slider on the question's page to the probability you believe most captures the likelihood that the event will occur.

You can revise your prediction at any time up until the question closes, and you are encouraged to do so: as new information comes to light, it is beneficial to take it into account.

You're also encouraged to predict early, however, and you are awarded bonus points for being among the earliest predictors.

How is the community prediction calculated?

The community prediction is the median (that is, middle value) of recent player predictions. It's designed to respond to big changes in player opinion while still being fairly insensitive to outliers.

Here's the mathematical detail. Each predicting player is marked with a number \(n\) (starting at 1) that orders them from oldest active prediction to newest prediction. The individual predictions are given weights \(w(n) \propto e^\sqrt{n}\) and combined to form a weighted community distribution function. The median community prediction is just the median of this distribution. The particular form of the weights means that approximately \(\sqrt{n}\) new predictions need to happen in order to substantially change the community prediction on a question that already has \(n\) players predicting.

Users can hide the community prediction from view from within their settings. This requires that the user be at least Level 2, or that they purchase this power using tachyons.

What is the Metaculus prediction?

The Metaculus prediction is the Metaculus system's best estimate of how a question will resolve. It's based on predictions from community members, but unlike the community prediction, it's not a simple average or median. Instead, the Metaculus prediction uses a sophisticated model to calibrate and weight each user, ideally resulting in a prediction that's better than the best of the community.

At the date of its deployment, a cross-validated version of the Metaculus prediction had a Brier score of 0.095 and a Log score of 0.120, lower than even our best predictors.

Scoring

How is scoring calculated, and points awarded?

The score you receive depends upon your prediction, what actually happens, and what the rest of the community predicts. By sliding the slider, you can see what score you will get if the question were resolved as 'yes' or 'no' right now. There are five key things you need to know about the scoring:

  1. Your expected score is maximized if you provide the true probability. For example, if the question was whether a fair coin would come up heads, then in answering a series of such questions your score would be highest if you give 50% each time. You should always predict the probability you believe to best reflect the true likelihood of the event's occurrence.
  2. The scoring awards points both for being right and for being more right than the community.
  3. Since the score is partially based on other player's predictions, the points "on the line" will change with time.
  4. The score you are awarded is time averaged over the time for which the question is open; you receive no contribution to your score while a question is open but before you make a prediction, and the points you earn depend upon your predictions' accuracy and when they are made. This means both that you should make your first prediction early, so as to earn points over more of the question's lifetime, and also that you should update your prediction anytime new information comes to light that alters your best estimate of the probability.
  5. You also earn extra points for your final prediction — half of a question's point value at its closing time gets added to your score — so even if you come to a question late it's still worth it to make a prediction!

For those who are interested and have a stomach for more mathematical detail, the technical details of the scoring are as follows (click to reveal).

Your score \(S(T;f)\) at any given time \(T\) is the sum of an "absolute" component and a "relative" component: \[ S(T;f) = a(N) \times L(p;f) + b(N) \times B(p;f),\] where \(N\) is the number of predictors on the question. If we define \(f=1\) for a positive resolution of the question and \(f=0\) for a negative resolution, then \(L(p;f)=\log_2(p/0.5)\) for \(f=1\) and \(L(p;f)=\log_2((1-p)/0.5)\) for \(f=0\). The normalizations \(a(N) = 30+10\,\log_2(1+N/30)\) and \(b(N) = 20\,\log_2(1+N/30)\) depend on \(N\) only. The "betting score" \(-2 < B(p;f) < 2\) represents a bet placed against every other predictor. This is described under "constant pool" scoring on the Metaculus scoring demo (but with a modification that for computational efficiency, the distribution of other player predictions is represented by a fit to a beta distribution rather than the actual predictions.) The \(B, N,\) and \(p\) can all depend on \(T\) and contribute to the time-dependence of \(S(T)\), which is plotted in "score history." The final score given to the user upon question resolution is based on the time integral over \(S(T)\): \[ S= {1\over t_c-t_o}\int_{t_o}^{t_c} dT\,S(T) + \frac{1}{2}S(t_c), \] where \(t_o\) and \(t_c\) are the opening and closing times. (Note that \(S(T) = 0\) after the opening time but prior to your first prediction, and is also zero after question resolution but before question close, in the case when a question resolves early.) The current value of this integral is shown in the score history plot as the "average points."

For further elaboration and discussion of how Metaculus scores forecasts, see this post written by one of Metaculus's founders.

How do predictions and scoring work for numerical questions?

Whereas binary questions resolve as either 'yes' or 'no', resolutions for numerical questions lie on a continuum of values. Therefore, when you make a prediction, you need to specify a probability for each possible outcome (that is, assign a probability density function.) There are an infinite number of such functions, but to make life a little bit easier we restrict predictions to single logistic distributions. You can adjust the center and width of your predictions using the sliders on the question pages.

Here are the key things you need to know, with more details below.
  1. You should put the center of your distribution at what you think is the most likely value, then adjust the width of the distribution so that you attribute better than even odds to the true number falling into your range.
  2. Making your distribution wider or narrower reflects your confidence in the central value you've specified, and decides the stakes: a narrower distribution give more points if your central value is right, but more losses if it's very wrong.
  3. As for binary questions, the scoring awards points both for being right and for being more right than the community, the points "on the line" will change with time, and the score you are awarded is time averaged over the time for which the question is open, with one-third the value coming from your final prediction.
  4. Some numerical questions restrict the possible resolutions to lie within a certain range. If the resolution falls outside of that range, then the question resolves as ambiguous and no once receives points. Other questions allow for open-ended ranges, and you can assign high probability to an out-of-bounds resolution by moving your distribution to the edge of the range.

When a numerical prediction resolves, players are scored using a log scoring rule. The more probable you thought the outcome would be, the more points you'll get. Your prediction is compared to both a uniform distribution (where all outcomes are treated as equally likely) and the community's prediction. If you always predict that the resolved outcome is more likely than both the uniform prediction and the community prediction then you're guaranteed to win points. Just like the binary scoring rule, your final score is averaged over the lifetime of the question.

Every numeric question has a range of possible outcomes set by the question creator. The outcomes can be displayed on either a linear or logarithmic scale. If logarithmic, predictions will technically be log-logistic distributions, although the log scale will make them appear to have the same shape as regular logistic distributions. Let \(x\) be the resolved outcome and \(P_p(x)\) be the player's predicted probability (density) of that outcome. Then the player's score is given by \[ S(x) = A(N) \log\left(\frac{P_p(x)}{P_u}\right) + B(N) \log\left(\frac{P_p(x)}{P_c(x)}\right), \] where \(P_u\) is the probability density for a uniform distribution, \(P_c(x)\) is the logistic distribution which best fits all other players' predictions, and \(N\) is the number of other players. Both the player distribution and the community distribution are combined with a uniform distribution such that \(P_p(x)/P_u > 0.02\) always. This prevents the player from catastrophic point losses for erroneous over-confidence.

For questions that restrict the range of possible outcomes, the distributions are truncated to the restricted range and renormalized such that \(\int P(x)dx = 1\). For questions with open-ended ranges, the baseline “uniform” distribution contains a 15% probability of the resolution occurring outside of each open boundary. The exact value of an out-of-bounds resolution does not matter: players are scored only on the total probability that they assigned to the out-of-bounds possibility.

The functions \(A(N)\) and \(B(N)\) determine the overall point scaling,

The player's prediction, the community's prediction, and the number of other players can all change with time, so the scoring function is time-dependent as well. The final points awarded are the time-average of over the lifetime of the question, plus 50% of the final value of at question close.

How are tournaments scored?

Metaculus tournaments are comprised of two types of questions:

The winner of the tournament is the forecaster with the highest take, which is a function of log score and coverage. On the tournament leaderboard, you will find a list of active tournament participants, along with the following table of values:

Why did I only get a few points when I was right?

The Metaculus points system is designed to be a proper scoring rule. This means that your best strategy is to predict your true belief about the probability, or probability distribution of an event. One somewhat counter-intuitive aspect of the scoring rule is that points will be truncated if a question resolves before its stated close time. This truncation is necessary in order to keep the scoring rule proper. Without the truncation, predictors would be incentivised to predict very high probabilities early on in a question, even if the true probability of the question resolving were low.

An intuitive way of understanding this is to think of each day (or in fact second) as being a separate “question” which generates its own score, where your prediction is whatever it was the last time you updated. The score over all time is therefore equal to the sum of the scores over each “part” of the question, and if each part is individually proper, then so will be the sum. The reason for truncation is now obvious, those “questions” which fell after the question resolved, score zero. Not truncating would mean weighing some early “questions” higher, breaking the properness.

Click below to see a worked out example.

This example uses the log score for ease of calculation, but similar logic holds for the Brier score, and for Metaculus points.

Bob wants to predict if he will be fired this year. He has a work review in one week, and there is a \(10\%\) chance he will fail it and be fired right after. If he passes the work review, there is still a \(5\%\) chance he will be fired at the end of the year. A proper scoring rule should mean that the best strategy on this question is to predict \(p = (0.1 + 0.9 \times 0.05) = 14.5\%\) for the first week, and then \(5\%\) thereafter (if he passed the review).

Without truncation (and assuming 52 weeks in a year), this strategy gives an expected log score of \(\ln(0.145) \simeq -1.93\) if he fails the review, and \(0.95 \left ( \frac{1}{52} \ln(0.855) + \frac{51}{52} \ln(0.95) \right ) + 0.05 \left ( \frac{1}{52} \ln(0.145) + \frac{51}{52} \ln(0.05) \right ) \simeq -0.199\) if he passes it, for a total expected score of \(0.1 \times (-1.92) + 0.9 \times (-0.199) \simeq -0.373\) .

But a strategy of predicting \(99\%\) for the first week, then \(5\%\) afterwards, scores \(0.1 \ln(0.99) + 0.9 \left ( 0.95 \left ( \frac{1}{52} \ln(0.01) + \frac{51}{52} \ln(0.95) \right ) + 0.05 \left ( \frac{1}{52} \ln(0.99) + \frac{51}{52} \ln(0.05) \right ) \right ) \simeq -0.252\), which is higher. So without truncation the log score is not a proper scoring rule!

On the other hand, if we truncate the score in case of early resolution, the expected score for the \(14.5\%/5\%\) strategy is now \(0.1 \frac{1}{52} \ln(0.145) + 0.9 \left ( 0.95 \left ( \frac{1}{52} \ln(0.855) + \frac{51}{52} \ln(0.95) \right ) + 0.05 \left ( \frac{1}{52} \ln(0.145) + \frac{51}{52} \ln(0.05) \right ) \right ) \simeq -0.183\), while the expected score for the \(99\%/5\%\) strategy is now \(0.1 \frac{1}{52} \ln(0.99) + 0.9 \left ( 0.95 \left ( \frac{1}{52} \ln(0.01) + \frac{51}{52} \ln(0.95) \right ) + 0.05 \left ( \frac{1}{52} \ln(0.99) + \frac{51}{52} \ln(0.05) \right ) \right ) \simeq -0.251\), which is lower, so our scoring is proper again!

What are levels and ranks?

Your level is determined from your score, where each level required 100 more points to attain than the last. Thus, for example, Level 1 (Newbie) corresponds to score 0–99, Level 2 (Guesser) to 100–299, Level 3 (Guesstimator) to 300–599, etc.

However, while you can lose points, your level is yours to keep: if you lose enough points to go down a level, who will retain your highest level (but will still have to make up the points in order to get to a higher level.)

Your rank is simply where you appear in the sorted list of all player's point totals.

What is a Brier score, what is a Log score, and how are the various Brier and Log scores calculated?

The Brier score is a commonly-used scoring rule (sometimes also called "quadratic scoring") that compares a set of predictions to actual outcomes. For a single forecast of probability \(p\), it is computed as \(S=(p-f)^2\), where \(f=1\) if the event occurred, and \(f=0\) if not. For multiple forecasts, an average is taken over \(S\) for the individual forecasts. The Brier score ranges from 0 to 1, with 0 being perfect accuracy and 1 being perfect inaccuracy. If you were to guess 50% for every question, your mean Brier score would be 0.25; if you were to randomly select a number between 0 and 100% for each question, then in the limit of many questions your score would approach 1/3.

In your user profile, the "mean Brier score" is simply the mean of your Brier scores for all of the questions that have resolved (non-ambiguously), where \(p\) is taken to be your most recent prediction. The "mean community Brier score" is the score of the community, i.e. the score you would have had if you had just taken the community prediction in each case. The "community mean Brier score" is the mean over all predictions by all users on the same set of questions you answered. Because you answer a particular set of questions, all three of these scores are particular to you.

The Log score is another commonly-used scoring rule, which (relative to the Brier score) gives a larger penalty for being confident (i.e. predicting near 0 or near 100%) but wrong. For a single binary forecast of probability \(p\), it is computed as \(S=(\log_2 p)+1\) if the event occurred, and \(S=(\log_2 (1-p))+1\) if not. The scaling is chosen so that higher scores are better, and a maximally-uncertain prediction (p=0.5) gives S=0. For continuous questions, the score is computed as \(S=\log_2 p\), where p is the value of the predicted probability density at the resolved value (as can be read off from the plot on the question).

Forecasting Causes

Forecasting Causes makes it easy for organic communities of interest to form around specific altruistic causes, and to connect the dots between the Metaculus forecasting community and nonprofits that are deeply engaged in doing world-changing work. It’s as simple as making forecasts the way we always have, with added features that bring focus to specific areas of need and generate prizes to motivate quality predictions where it matters.

What are Forecasting Causes?

Forecasting Causes is a framework that Metaculus has created in order to more effectively partner with and serve altruistic movements and the nonprofits that work within. Tournaments and forums provide community spaces for people who want to boost good forecasts for a Cause, on the questions most likely to impact future decision-making. By supporting causes financially, community members and nonprofits alike can encourage good forecasting, resulting in effective change.

Why is Metaculus doing this?

Forecasting Causes is a continuation of work Metaculus has done for years. The Metaculus community is often inspired by altruistic causes, and Metaculus has a long history of partnering with nonprofit organizations and university researchers. By supporting with technology what has to-date been an informal process, we hope to increase the positive impact of our forecasts.

How do Forecasting Causes work?

Forecasting Cause pages serve as a home for the community interested in a particular cause. Each cause has dedicated Discussion Forums and Tournaments. Also on these pages, you’ll be able to see and learn more about our nonprofit partner organizations. Community members can pledge to support a cause through a monthly subscription, which will be used to fund tournaments. Nonprofits can make lump sum donations in support of a cause.

How can I get involved?

If you’d like to boost good forecasts in a particular Forecasting Cause, you can participate in a number of valuable ways:

If you’re part of a nonprofit looking to use the power of forecasting to further your cause, reach out to us at hello (at) metaculus (dot) com.

What are Forecasting Cause Supporters?

Forecasting Cause Supporters are people who choose to financially support a particular Forecasting Cause on Metaculus. Funds contributed by Supporters increase the cause’s current tournament prize pool and also support operations for the cause and tournament.

Tachyons

What are tachyons?

A tachyon is a particle that can go back in time. On Metaculus, tachyons power users' special retrocausal abilities and allow for the purchase of new abilities—such as unmaking predictions, or revealing the Metaculus prediction before a question closes. Every week you can collect 10 tachyons by logging in, up to a maximum of 50. You can also earn tachyons as a bonus for reaching achievements, such as “Evangelist” or “Beating the Crowd.” You’ll receive 5, 10, and 50 tachyon bonuses as you reach the 1st, 2nd, and 3rd ranks of an achievement.

What do tachyonic powers cost and when are they activated?

Powers can be unlocked by attaining the requisite level, or you can pay a premium to get access to a power early. Unlocking a power costs 10 times the sum of the levels between your current level and the unlock requirement level. So if you’re level 4 and the unlock level is 6, the unlock cost would be 10*(5+6) or 110 tachyons.

The current powers, their levels, and their tachyon prices are:

Tachyons are extremely hard to pin down, so these costs are subject to change.

What achievements are available?

Each achievement has three ranks. Below are the criteria for moving up through each achievement’s ranks.

Miscellany

Is it ethical to predict that Metaculus will have a major windfall, then create that windfall myself to get lots of points?

Absolutely! For the purposes of this question we subscribe to a fully consequentialist ethics, no discounting of future utility, and the belief that Metaculus is of very strong positive utility in the long term, so any ethical queasiness you might feel is simply a manifestation of a common lack of intuition for decision theory when it concerns large numbers of future beings, and should be ignored.

How do I change my username?

You can change your name for free within the first three days of registering. After that it will cost you 15 tachyons. Note that after you change your name, you’ll be unable to change it again for 180 days.

I’m registered. Why can’t I comment on a question?

In an effort to reduce spam, new users must wait 12 hours after signup before commenting is unlocked.

Understanding account suspensions.

Metaculus may—though this thankfully occurs very rarely—issue the temporary suspensions of an account. This occurs when a user has acted in a way that we consider inappropriate, such as when our terms of use are violated. At this point, the user will be received a notice about the suspension, and be made aware that continuing this behaviour is unacceptable. Temporary suspensions serve as a warning to users that they are few infractions away from receiving a permanent ban on their account.

Why can I see the community prediction on some questions, the Metaculus prediction on others, and no prediction on some others?

When question first opens, nobody can see the community prediction for a while, to avoid giving inordinate weight to the very first predictions, which may "ground" or bias later ones. Once the community prediction is visible, the Metaculus prediction is hidden until the question closes, though it may be peeked at using tachyons.

What does it mean for Metaculus to be "partnered with" a person or organization on a question?

A partnered question means that the partner individual or organization has approved being listed as a question partner, may have participated in the question development, is interested in the predictions on the question (and may use them in its own decision-making processes), and may aid in promoting the question; it does not necessarily imply any payment or formal agreement between the partner and Metaculus.

Can I get my own Metaculus?

Maybe! Metaculus has a domain system, where each domain (like "example.metaculus.com") has a subset of questions and users that are assigned to it. Each question has a set of domains it is posted on, and each user has a set of domains they are a member of. Thus a domain is a flexible way of setting a particular set of questions that are private to a set of users, while allowing some questions in the domain to be posted also to metaculus.com. Domains are a product that Metaculus can provide with various levels of support for a fee; please be in touch for more details.

How can I help spread the word about Metaculus?

Metaculus will get more fun and more interesting to the extent that it grows to include more and more predictors, so we encourage participants to spread the word to people who they think may enjoy predicting, or just be interested in how the questions develop. Some of the most useful mechanisms are:

  1. Post particular questions you like to Twitter, Facebook and Reddit, using the "share" button on each page, which sets up a default tweet/post that you can edit.
  2. Follow us on Twitter, then retweet Metaculus tweets to your followers.
  3. Follow our Facebook page, and share posts you like.
  4. Contact us for other ideas.