The definition and the math
Take a fixed set of buyer questions. Run each through ChatGPT, Gemini, Claude, and Perplexity multiple times. AI share of voice = your mentions divided by total brand mentions across all sampled answers. Track it per question, per assistant, per month, and it behaves like any other competitive metric: it trends, it responds to work, it predicts pipeline.
Why it beats mention counting
Raw mention counts flatter you in growing categories: everyone’s mentions rise as usage grows. Share of voice is zero-sum, so it shows who is actually winning the answers. A rising count with falling share means competitors are growing faster inside the same conversations, which is exactly the signal a count alone hides.
Position weighting matters
Being named first in an answer is not the same as being the “also consider” at the end. Sophisticated share-of-voice scoring weights first mentions and recommendation framing above passing references. Aethon scores both, because buyers overwhelmingly act on the first confident name.
What moves share of voice
The same levers that create AI visibility, weighted competitively: presence in the citations assistants lean on, quotable comparison content, review consensus, and coverage of the conversational moments where your competitors are currently the default answer. Every point of share you gain is a point someone else loses.
Reporting it
One table: rows are your priority questions, columns are the four assistants, cells are your share versus the leader’s. Executives grasp it instantly because it looks like market share, and it is: market share of the answers buyers hear. Aethon reports it monthly with the before-and-after answers that explain each move.