(The answer is "groups"... whenever you can.)
In the New Product Blueprinting process, you’ll first conduct a round of qualitative, divergent Discovery interviews… and then go back to (mostly) the same companies for a round of quantitative, convergent Preference interviews.
You might be tempted to conduct individual interviews—which let you focus on the person’s expertise and provide a “safe” environment—but it’s generally better to interview several B2B contacts at the same time. (In most B2B industries, they will all be from the same company, due to inter-company rivalry.)
Whenever possible, you should conduct group—not individual—interviews… but the reasons for this are different for Discovery vs. Preference interviews. Discovery interviews feel like a brainstorming session, with ideas captured on sticky notes and any idea welcome. (We would never call them “brainstorming,” though, because we don’t want to encourage “solutions.”… just desired customer outcomes.)
Have you ever been in a brainstorming session… by yourself? Probably not. That’s because you want to build off each other’s ideas, have time to think of your next idea, etc. The same is true for your Discovery interviews. Yes, you can have a successful interview with one person, but you’ll generally do better with group interviews.
It’s even more important to have group interviews for the Preference phase. You need to get all the major decision-makers and decision-influencers into these interviews… even if you use a web-conference to do so. Imagine you ask how important it is to “increase abrasion resistance” on a 1-to-10 scale. The marketing person gives it a “9” and the operations person says it’s a “3.” What do you do? Let them debate the issue, while you listen and learn.
If they can’t agree, ask, “From the standpoint of your entire company, how important is this?” At this point, the operations person might say, “Well abrasion-resistance doesn’t help my department, but if marketing can sell more, then I guess it’s a 9.” If you had interviewed them individually, you’d have absolutely no idea what the right answer was.
For more, see e-Learning Module 10: Interviewing Fundamentals at www.blueprintingcenter.com > e-Learning.
Keywords: group interview, individual interview, Discovery interview, New Product Blueprinting, customer decision-maker, customer decision-influencer, customer debate, springboard