What is a persona?
A persona is an archetype for a type of user, based on grouping many similar users together and synthesizing their attributes into a single fictive user with a name. Great products are developed with empathy for the user. However, it is not possible to emphasize with a multitude of users directly. By working with personas, that becomes possible.
When working with Opportunity Solution Trees, and trying to aggregate lower-level opportunities into higher-level ones, it is sometimes a good idea to try substituting the top-level opportunities with different personas.
Persona creation is part of user and problem discovery in the product management process.