The persona [is] a package for containing what you’ve learned from your field research. A package that is transportable to everyone on the team, so they can have the same benefits of knowing the users as you have.Jared Spool is a usability professional. His job is field research. While research is incredibly important, I don't think it's the be-all and end-all. So long as the people feeding into the persona creation process are people who genuinely understand the website user through first-hand experience.
In the interview, Steve Mulder gives this opinion:
I think personas not based on actual user research are absolutely better than no personas at all. A lot of customer and user knowledge already exists in many organizations, and by looking at the sales, marketing, product, customer support, and tech support perspectives, you can bring all these existing bits of knowledge together into personas without talking to any actual end user.Making Personas Work for Your Web Site: An Interview with Steve Mulder - by Jared Spool
Crappy Personas vs. Robust Personas - blog post by Jared Spool
Personas vs. User Descriptions; Apples vs. Tomatoes
A final observation from Jared Spool:
Recently we conducted a study of several dozen organizations who claimed to use personas. Less than 5% actually conducted field research to inform their personas. The remaining 95% just made up the descriptions from internal guesswork.
If you’re just going to guess on the personas, why bother?