GAUGE
The Calibration Instrument.
WHAT IT IS
GAUGE is a calibration and estimation trainer for iPhone and iPad. It measures the one skill almost nobody measures: knowing what you don't know. Most people who say they are "90 percent sure" turn out to be right only about half the time. GAUGE scores how well-calibrated your confidence and judgment actually are, and helps you train them.
It is a real instrument and a genuinely fun game at the same time. There is no timer, ever. GAUGE measures judgment, not speed.
FOUR WAYS TO ANSWER
- RANGE: give a 90 percent confidence interval on a two-thumb slider. Catch the truth inside your band, but narrower bands score higher.
- CLAIM: judge a statement true or false and set your confidence.
- OVER or UNDER: a value is shown, and you decide whether the truth is over or under.
- FERMI: order-of-magnitude estimates on a log scale, for when a rough answer is the whole point.
Pick a mix or focus on a single domain: geography, history, science, numbers and money, culture, and your locale. Choose sets of five, ten, or twenty questions.
YOUR SCORE, IN THE OPEN
GAUGE gives you a transparent 0 to 100 score built on proper scoring, plus coverage, sharpness, and a grade. A "how it's scored" screen shows exactly how the number is calculated. No black box.
THE LAB
The Lab is where your judgment becomes visible. See your calibration curve: your stated confidence against your real accuracy, plotted against the perfect diagonal, with overconfident points highlighted. See your coverage against the target, and a breakdown of where your judgment is sharp and where it leaks by domain. Baselines compare you to the roughly 52 percent human average and to a frontier AI, so you can find out whether you are better calibrated than an AI.
DAILY TEN
Everyone in the world gets the same ten questions once a day. Build a streak and share a spoiler-free result grid. An activity heat map tracks your active days, longest streak, and best grade.
A LITTLE AI, A LOT OF LEARNING
After each set, a short AI micro-insight tells you what your answers reveal. Tap "why" on any answer for a sentence of context. Every reveal shows the truth with its source, so each question is a small lesson.
PRIVATE BY DESIGN
GAUGE runs on your device. No account, no sign-up, no login. No tracking, no ads. You can export your record as a CSV file or delete everything anytime.
BUILT FOR IPHONE AND IPAD
A universal app with a warm-paper light theme and a dark terminal theme, in a clean monospace style.
FOR THE CURIOUS
GAUGE is for people who love trivia and quizzes but want something smarter, for forecasters, and for anyone drawn to decision-making, critical thinking, probability, cognitive bias, mental models, and self-improvement.
Start with a set of ten. Find out what your "90 percent sure" really means.