duck_master

Have you ever wanted to predict the future? Did you ever take a peek at Metaculus or Manifold or some other site, suddenly feel super intimidated about the effort you'd need to put in, and never try again? If so, fear not, for this post is for you![1] This post is intended to be a how-to guide. I will add pictures because apparently people really like reading posts with pictures. However, since there are exactly zero good explainers on how to be a good predictor as far as I know, I'm hoping that more experienced predictors will find value in this post too. Thanks to Emily Thomas for proofreading this post! Epistemic status/content warnings: Basically correct in the big picture, but I might have missed or misstated some details. May be too wordy or technical in parts. 1. What is probabilistic predicting, anyways? Throughout history, people have often been interested in predicting the future. In ancient times, people would ask the local prophets or soothsayers. (This is called "prophecy", and it's mostly extinct.) In more recent decades, they have tried other, more systematic approaches, such as extrapolating trend lines on a graph into infinity. (This was called "futurism", and it still exists to some extent these days.) Needless to say, the track record of such efforts is pretty bad. The key insight of probabilistic prediction is simple: Instead of saying that things will definitely happen, just soften it to saying that they will only probably happen. And quantify the probability! 1.1 What is probability? Probability is a weird and mystical concept that does not sit well with some people. For our purposes, a probability is a number associated with an event that describes what fraction of the times it could happen that it actually does happen. For example, if an event has a probability of 0.8, then given 10 different chances, the event should happen about 8 times. To make our lives easier, we predictors usually use percentages to write probabilities (for exam