The interviews seemed free-form and they change based on your answers but in general, there were no market sizing questions and all the questions were behavioral regarding your experience in product. I would recommend preparing some stories that show grit, and measured iterative change to a digital or physical product. Be ready to explain how you thought a user would use a product, how it was actually being used, and how you learned about their genuine usage patterns from some form of data gathering or user interviews after a release. I would guess the ideal story would be something like: My team did our research and the data suggested customers wanted product X. We built product X with input from engineering, user research, and sales. There was some adoption of product X but not as much as we expected. I reached out to members of other to find out why this product wasn't meeting projections, then I looked into usage data and found a strange drop off in the sign-up flow. I then spoke with a user arranged a time to watch them use product X. When they used it I realized our team had misunderstood one of the main use cases. We made a change in our next release and sent a message to our current users explaining how we changed Y so they could do Z. This lead to a 369% increase in daily active users compared to the first month. Be sure to phrase your questions in the SAR framework. Situation (low usage of product) Action ( research using: data, user interviews, and team members) Result (Increased product adoption).