← All articles · September 2026 · 3 min read
Prediction Tracker: Why Write Your Predictions Down
Memory rewrites what you predicted. A dated record does not. How to track predictions, and which tools do which part of the job.
Memory Is a Bad Prediction Tracker
Everyone makes predictions: this product will flop, that hire will work out, rates will fall before summer. Almost nobody writes them down, and memory is an unreliable record. Psychologists call the problem hindsight bias. In a well-known 1975 study, Baruch Fischhoff and Ruth Beyth asked people to rate the likelihood of possible outcomes of President Nixon's 1972 trips to Beijing and Moscow before they happened. Asked afterwards to recall their own estimates, many remembered giving higher probabilities to the things that had actually happened. Once we know the outcome, we quietly edit what we thought we knew.
A prediction tracker is simply a way to stop that edit: write the prediction down, date it, and check it when the outcome is known.
What Makes a Prediction Trackable
Most everyday predictions cannot be scored because they are vague. "The economy will slow down" can be declared right or wrong after almost any outcome. A trackable prediction has four parts:
1. A specific, observable outcome — "US quarterly GDP growth below 2%, as first reported by the BEA".
2. A deadline — "for Q3 2026", not "soon".
3. A probability — "70%", so a miss at 70% is treated differently from a miss at 99%.
4. A resolution source — who or what decides whether it happened.
If a neutral friend could not settle the question from your wording alone, rewrite it before you log it.
Scoring: Hit Rate Is Not Enough
Counting hits and misses rewards people who only predict safe things. Forecasters use calibration and proper scoring rules instead. Calibration asks: of all the things you said were 70% likely, did about 70% happen? The Brier score, proposed by the meteorologist Glenn Brier in 1950 for weather forecasts, measures the squared distance between your probability and what happened (1 or 0), so it punishes confident misses hardest. You only need a spreadsheet to compute both once you have a few dozen resolved predictions.
Which Tool Does Which Part
Tracking predictions has three separate jobs, and no single tool has to do all of them.
Logging and scoring: a spreadsheet works — one row per prediction with the date, wording, probability, deadline and outcome. Public forecasting platforms such as Metaculus and Good Judgment Open let you forecast on questions they define and score you against other forecasters.
Proving the date and wording: a spreadsheet or a note can be edited later, and other people have to take your word for it. That is the gap a timestamp fills. It fixes the exact wording and a date that nobody, including you, can change afterwards.
Reviewing: set a calendar reminder for each deadline and a quarterly review of what you got wrong.
Where icalledit.io Fits — and Where It Does Not
icalledit.io does the "prove the date and wording" part. You write the prediction (you can add fields such as "Probability: 70%" and "Resolves: 30 Sep 2026"), and a SHA-256 hash of that record is written into its own Bitcoin transaction. You get a PDF certificate and a proof.json file, so anyone can check later that this exact text existed by that date — without relying on our website. The verification page shows your title and name only if you switch that on.
It is not a scoring app: it does not resolve predictions, compute accuracy or keep a public leaderboard. Keep your scorecard in a spreadsheet or on a forecasting platform, and use a timestamp for the calls you will want to prove later. One registration costs $19; the preview is free and is not written to Bitcoin.
Start Small
Write down five predictions this week that resolve within three months. Give each a probability and a resolution source. When they resolve, score them honestly, including the ones you would rather forget. That habit, not any app, is what makes you better at predicting.
A timestamp proves that content existed at a point in time. It is not legal advice, a patent, a trademark or a copyright registration. Compare the options.