KPI
1 min read · Reviewed 17 Oct 2026
In short
The one number that tells you whether something is working.
In plain English
A key performance indicator — the specific measure you have agreed to judge something by, chosen in advance.
A real example
For an AI support assistant: average first-response time. Not "messages handled", which rewards volume, and not "satisfaction", which moves too slowly to steer by.
Why it matters
Choosing it before you start is what makes evaluation honest. Chosen afterwards, you will pick the number that makes the decision look good.
