Share of voice
How often AI engines mention your brand versus competitors across a set of prompts.
Share of voice is the comparative metric, which is what makes it useful. A raw mention count tells you that you appeared. Share of voice tells you whether you are winning or losing the answer against specific rivals.
If an engine names a competitor in eight of ten category questions and you in three, the problem is concrete and you can prioritize it. This is usually the most actionable number in AI visibility.