An opinion says 'I believe.' An assumption says 'I can test.' Only one of these leads to better decisions.
A testable assumption follows this form: If I do X, then Y will happen — and I can prove it within one week.
Why this matters: testing assumptions in days prevents wasting months on strategies that don't work.
A startup assumed customers wanted feature X. They tested in 5 days with a landing page — only 2% clicked. Saved six months.
Pitfall: treating your assumptions as already-proven. Strong feelings about what's true are your biggest testing blind spot.
Great judgment tests assumptions in days before committing months. Make your beliefs earn their place.
An opinion can't be tested. An assumption can. Today you convert one into the other.
Today's practice: pick something you currently believe about a project or decision.
Step 1: write your belief as a testable statement — If I [do X], then [Y will happen].
Step 2: add the test. 'I can prove this by [specific action] within [timeframe].' Make it real and soon.
Commit: write one testable assumption today. Run the test this week. Let data replace opinion.
A compass that has been tested points truer. Every assumption you prove sharpens your judgment for the next decision.
