When I conduct interviews with potential customers I like to do it in two rounds.
The first round is an online questionaire that establishes the base and provides context for the interview. Customers agree to filling it out and are usually very good at it. What it does is that it helps me understand them and where they are coming from a little bit more before the actual interview, so we can make the most of our time together.
When I then sit with them for the interview itself, we don’t have to waste time establishing the baseline. We can go directly into talking about the stuff that matters to the customer, and I can use the info from the questionaire as background and context and thus get the best possible outcome of the interview.
It always give the best results.