What is forecasting?

Saul Munn asks:

I haven’t been able to find many really good, accessible essays/posts/pages that explain clearly & concisely what forecasting is for ppl who’ve never heard of it before. Does anyone know of any good, basic, accessible intro to forecasting pages? Thank you!

(something i can link to when someone asks me “what’s forecasting???”)

In general, forecasting refers to the act of making predictions about future events. Generally these predictions are numerical—"A 25% that Trump will be president in 2025“—and they are generally made with the objective of improving one’s models of the world. It’s easy to pretend to have models, or to have models that don’t really help you navigate the world. And at its best, forecasting helps you to acquire and create better models of the world, by discarding the hypotheses that don’t end up predicting the future and polishing those that do. Other threads that also point to this are "rationality”, “good judgment”, “good epistemics”, or “Bayesian statistics”.

Personally, I like to situate forecasting in terms of becoming stronger and more powerful. I want to become stronger and more powerful, so I try to have good models of the world. And looking at ways to have good models of the world, forecasting stands out among them.

Several threads to look into are:

• Philip Tetlock’s research, and his book Superforecasting. In this book, Tetlock outlines some of the basic practices to make better predictions.
• Prediction markets like Polymarket, where people wager money on the outcomes of events. Over many bets, on average, if a contract for an event is trading at 60cts on the dollar but happens 80% of the time, you can make money (though see caveats). And losing money when wrong can be a powerful motivator for disenchanting oneself with incorrect hypotheses.
• Forecasting platforms, like Good Judgment Open, Metaculus, or Manifold Markets, where people keep track of their predictions but don’t put money on the line.
• Subjective Bayesianism, like in E. T. Jaynes' book Probability Theory: The Logic of Science (available in e.g., Anna’s Archive). This can be a pretty hit-or-miss book; if you don’t like it, maybe look at this thread of textbook recommendations.