FoMind
The forecast says “70% chance of rain tomorrow,” and then not a single drop falls. Was the forecast wrong? Not necessarily. Seventy percent means that across many days like tomorrow, it rains on about 7 out of 10. Tomorrow just happened to be one of the other 3 — that alone doesn’t make the forecast bad.
Probability is how sure you are
In forecasting, a probability expresses how confident you are that something will happen. Saying 70% means: “If I made 10 calls at this level of confidence, about 7 would come true.” So no single outcome proves you right or wrong. What matters is whether, over many forecasts, the things you call at 70% happen about 70% of the time.
That has a few consequences:
- Use 0% and 100% sparingly. Saying 100% means “there is no way I’m wrong,” and very little in life is that certain.
- 50% isn’t a catch-all for “I don’t know.” It means you think both outcomes are equally likely. If you have any clue at all, lean one way.
- Probabilities are allowed to move. Changing your number when new information arrives isn’t flip-flopping — it’s updating.
The trouble with fuzzy words
In everyday life we say “likely,” “probably,” or “doubtful.” The problem is that the same word means very different things to different people: to one person “likely” is 60%, to another it’s 90%. Your manager says the project is “likely to get approved”; you hear 90%, while they meant 60%.
Try the sliders below: first set what “likely,” “possible,” and “unlikely” mean to you, then see how widely other people’s answers spread.
This is where the interactive demo “How likely is “likely”?” lives: in the FoMind app you can drag the controls and see results update live.
A probability is your degree of confidence — putting it in numbers is the only way others know how sure you really are.