If you are asking this question, kudos to you because you are taking the proactive approach. You are not doing what’s convenient (“Who will respond to me?”) or what’s reactive (“I am pulled into this conversation.”). 

So, who should you interview on product topics? It depends. Consider this: 

1. Ideal customer profile (ICP)

This is like a company. ICP can be simple (size, geo, vertical) or sophisticated (tech stack, goals/pains, behaviors). Startups that have product-market fit or scale-up companies should already have defined their ICP.  

So, prefer ICP over non-ICP to interview. Consider ICPs who are not yet customers, for example, prospects, those who use competitors or alternatives, or those not ready to buy. If your product’s market penetration is small, prospect interviews can yield different and valuable insights. 

2. Personas to serve

This is like a person. Interviewing them yields clarity on their jobs to be done. Depending on the topic, you may need to interview one or more personas. For SaaS products, interviewing multiple personas at the same ICP company yields rich insights. The ultimate product will need to trade-off which persona(s) to serve better than others; very few products serve everyone. 

So, prefer the higher-priority persona to interview, and also include other personas. The buyer persona or the influencer persona may be higher priority than the user persona. Interview not only the promoters of your product, but also the skeptics and the detractors. For B2B2C products, consider interviewing the end-user persona. 

3. Product vision, strategy, and stage

The ICP and personas inform, and are informed by, the overall product vision and strategy. So, prefer to select interviewees such that the insights inform the execution of the product strategy. In dynamic markets, the product strategy direction may change. Check: do the interviews intend to inform the current strategy or the product strategy direction?

Who to interview depends on the product’s stage: exploration, definition, development, release, growth, to name a few. Interviews for exploration, validation, satisfaction/escalation, and efficiency/delight are each different. 

A target list at the ready

Always be building the target list, not just when you need to do research. A simple way is to have an opt-in form included in outreaches, such as customer newsletters and surveys. Or make this form readily available, such as in the product, in-app notifications, or in community sites.  

Building a list of “not yet customers” requires more planning. For example, sales win/loss interviews could also include an opt-in question. Finally, there are apps and services available for recruiting interview candidates. 

How many customers to interview

This again depends. The Nielsen Norman Group reminds us to start with 5 users and do test-and-learn iterations.  

A related post is on 3 key questions for discovery. 

PS: Check out more articles on building products. I write to pay it forward and to clarify my thinking.