Definition
Plain language
Of the things a system flagged, how many it got right.
As stated in the literature
The fraction of positive predictions that are true positives; paired with recall and summarized by F1.
Why it matters: It tells you how trustworthy a system's alerts are, since low precision means many of its flags are false alarms.
For example, if a detector flags 100 emails as spam and 90 truly are spam, its precision is 90%.
Heard on the show
“On messy natural-language tasks the win is smaller but everywhere — and the practical precision is roughly thirty tokens of error on a four-hundred-token answer.”Episode 204 — The Length Estimate Hiding Inside a Word-by-Word Model