In the book, I talk a little bit about the idea of asking business folks and product managers to join me for the interviews. The idea is to involve them in hearing the customer's stories and also to get their direction if I'm exploring a topic that is new to me. Yes, sometimes the interviews are about chemistry or engineering, so I need a little coaching from people who live and breathe those subjects.
At the Agile 2008 conference a few weeks ago, Nick Gassman from British Airways came up to me to chat about his mental model project. Later he wrote to me with a suggestion about involving business and product folks in the interviews. Here's what he said:
"I was reading your book on a flight home, and on page 121 you refer to the misunderstanding between 'rooter' and 'router'. It's a frustration I've suffered at times from the other side of the fence. We've briefed the moderator, who then goes off-track, because they haven't understood the issue ... I now think that a pairing of a business-based UX person with the moderator would yield a better result. This would require some trust and agreed procedures between the two, but would allow the UX person to interject if the moderator had gone wrong somewhere, or to point out a missing link."
Nick brings up a great point: rather than waiting until after the interview as I had mentioned in the book, you can have someone around to keep you on-track during the interview. To avoid interrupting the flow of the conversation, I can imagine having a person with you in the room jumping up and down silently while pointing to a note on a whiteboard, as well as writing those same notes on IM if not co-located. These notes could keep an interviewer more on track and also be more "in the moment." I like it; thanks Nick!
Note: Remember to let the interview participant know that there will be someone listening in, and introduce that person at the start of the interview. In my experience, after the conversation gets going in the first few minutes, the participant forgets all about the other listener and converses naturally.