Visibility rate
Visibility rate is the share of sampled AI answers to a category prompt set that mention a brand at all, regardless of position or how many other brands were named. It is the simplest AI visibility metric and the one to read first, because it describes the brand alone rather than the brand relative to competitors.
Visibility rate versus share of voice
Visibility rate asks "was I in the answer?". Share of voice asks "of all the brands named, what fraction was me?". Read them together: share of voice up with visibility rate flat means a competitor lost ground, not that you gained it.
Sample size
Assistants answer differently every run, so a rate computed from five answers is noise. Ten answers per prompt and engine is a working floor, and the trend over weeks matters more than any single day. CitePrism greys out every rate below ten answers.