Persona

A single invented person who stands for a segment, detailed enough to argue with. It keeps the work honest about who it is for.

A persona earns its keep by being specific enough to disagree with. Give her a situation, a deadline, a previous disappointment, and she starts vetoing things: she would not read that headline, she has no patience for that onboarding. A vague persona vetoes nothing and becomes decoration.

The danger is fiction drift, a character assembled from the team's flattering assumptions. Personas must be built from encounters, interviews, support tickets, watching someone actually try the thing, and refreshed when reality argues back. She is a compression of evidence, or she is a puppet.