Acceptance rate
The share of AI code suggestions a developer accepts; the most common but weakest measure of assistant value.
Acceptance rate = accepted suggestions ÷ shown suggestions. Google reports 37% for internal code completion. It is easy to log and easy to game (shorter suggestions get accepted more), and accepting is not the same as keeping: code can be accepted and then rewritten. Better downstream measures are retained-character rate, task completion time and defect rate, which is why controlled studies such as METR's use task time rather than acceptance.