Share of model
Share of model is another name for AI share of voice: of the sampled answers that name any tracked brand, the share that name yours. It counts presence per answer, not raw mention counts. Read it per model, because each model answers from different data and can favor different brands.
Same metric, different name
Share of model and AI share of voice are one number. If 400 sampled answers named at least one tracked brand and 100 of them named yours, both are 25 percent. The label is a matter of habit; the formula, the sample-size floor and the need for a fixed prompt set are the same.
Where the term comes from
Marketers have long measured share of voice in advertising and media, and more recently share of search. Share of model extends the same idea to AI models, as brands began to ask how often assistants recommend them. The name puts the model at the center. Each model answers differently, so read the number per model.
Read it per model
Each model answers from different training data and retrieves from different sources, so a brand can hold a large share in one and almost none in another. An average across engines hides that. Read share of model per engine first, then overall, and next to visibility rate, because a share can rise when fewer answers name any tracked brand, even if you are named no more often.