Though personas are best created based on dozens of interviews, ideally enough where the interviewers can begin to predict what might be said next, the act of crafting personas on the fly are a helpful thinking tool. Splitting personas, renaming personas, merging personas, and discarding personas become part of the process where we identify previously unquestioned assumptions.
Personas created with just stakeholders or subject-matter-experts in the room are still very effective, as any target begins to reveal what thinking has ruled the roost this whole time.
Just as important to creating personas to represent who we are designing for, it’s important to identify who we are not designing for—previous obsessions of a particular stakeholder, the manufactured desirable user based on the technology looking for a market to deploy in, and an excessively hyper-competent super-user able to utilize all the sophistication the technology could deliver.
A persona could be created to stand in for the posture and voice of the product.
A well-considered persona set helps everyone begin to speak the same language, and discover where we were using the same words with wildly different definitions, actively use the part of our brain that understands people to encapsulate all the rich detail we learned from our users and the market.