# Don't guess, measure what matters

> Opinions are cheap and confident. A number you can check is neither, and it ends most arguments before they start.

Source of the line: Popular saying. Essay by Cosmin Cojocar. Theme: engineering. URL: https://cosmin.dev/creative-thinker/dont-guess-measure-what-matters/

Most technical debates are two guesses arguing. "The app feels slow." "The new model is better." "Users want this feature." Each sentence sounds like a fact and contains none.

Measurement turns a debate into a decision. How slow, on which device, for which action? Better at what, on which test set, compared with what baseline? A number does not have to be perfect to be useful. It has to be defined, repeatable and connected to something a user would notice.

The second half of the line matters as much as the first. It is easy to measure what is convenient: lines of code, tickets closed, hours logged. Those numbers move without anything getting better. Pick the metric that would change your mind, then let it.

## Try this

Take the next claim you hear in a meeting, including your own, and ask one question: what number would prove it wrong? If nobody can name one, it is still a guess.