1). How do you determine the number of interviews to conduct?
The ideal number of interviews is more than one. So many teams make decisions based on conversations with colleagues and executives. You need some real-world feedback to make decisions based on facts.
I’m told by experts in statistics that 31 is the ideal number but I’ve found you can usually get the answers you need by interviewing three to five clients… if they’re the right clients.
2). How do you chose the customers to interview? Is it any customer who will answer the e-mail, or do you have a screening process?
The ideal client to interview is the one who best represents your ideal client. Seems simple enough in theory but perhaps is harder to execute in practice. So, even if you don’t yet have customers, you should define a profile of the ideal client—what most people call a persona.
3). Is it possible/ethical to convert interviewed customer into product advocates?
It’s both possible and ethical. If you’re building a product that truly addresses the customer’s biggest problems, they’re very likely to want to stay involved. I’ve had such customers ask to be on my steering committee and they’ve paid they own expenses to come to demos at our corporate offices. When you tell someone about an exciting new product concept, you want to tell others. (Have I told you about my new Nest thermostat? It’s wonderful. Let’s talk!)
4). What are some of the key mistakes that product managers can make when developing and conducting customer interviews?
To quote Al Ries and Jack Trout, too many marketing people go through the motions of visiting customers, looking for facts that will confirm their previously formed opinions of what should be done.
5). How do you validate customer interviews? Do you simply conduct more interviews, or do you use an analytical validation technique?
I’m sure I should tell you about some fabulous data visualization tool but I’m rather old-school. I use post-it notes and tag clouds and highlighters to look for patterns in the data. After a few interviews I realize that I’m hearing the same thing again and again, usually with the same words. Beware of buzzwords and hot topics because they tend to be trendy rather than meaningful. "We want to institute best practices for using big data in social media.” (Uh, okay—what do you want me to, you know, actually do?)
At Applied Frameworks, for example, I hear people say "we need a playbook for how we do product management here” and "I need to way to make training stick.” So those are the services I’ve developed and the language I use to talk about them.
6). Do you have a template for structuring customer interview questions? What about open-ended questions to discover unmet needs?
In general, you use open-ended questions when you’re trying to discover and closed-ended questions when you’re trying to quantify. Nowadays most people combine these techniques. I use open-ended questions and additional probes to get to the root of the issue. I then use closed-ended questions to verify, using phrases like "How often does that occur?” and "What does that cost you in time or money?” So my mental template is like a series of funnels: open to closed on one topic, and then open to closed on the next topic.
I also use an interviewing roadmap with areas scoped out that I want to explore. It’s not a questionnaire as much a scorecard to make sure I addressed the important areas and didn’t forget anything after a side conversation.
One of my favorites final questions, one that I’ve used for years, is this one: "If you could sit down with my company president, what would you want to say?” Oh, and another good one: "What didn’t I ask that I should have?”
7). What didn’t we ask that we should have?
"What barriers do you see for product managers?” I see so many companies desperate for market insights. They all pretty much agree that product managers are the right ones to deliver the insights. They all want product managers to engage with clients. And then many of them put up innumerable barriers between product managers and clients.
One trick that I use is for product managers to build an "inner circle” of clients, usually people they’ve met personally and perhaps have done business with in the past. This inner circle of clients becomes a private group of councilors—people you can call for a quick question or to get feedback on a product concept or a positioning message or just for insight on an industry trend. The trick is: we don’t have to go through sales or legal to talk to our inner circle. But that requires a high level of trust. You have to know they won’t tell others (including their sales people); they won’t blog or tweet about it; what we discuss forever stays off the record. So don’t let anyone in your circle that you don’t trust.