Interviews are cheap; decisions are not. The Harvard Business School Rock Center notes that the most common discovery mistake is proceeding to a solution without validating the need, and that discovery has to stay an ongoing, iterative process because circumstances and needs keep changing (HBS Rock Center). That warning is usually read as advice about interviewing. It is really advice about synthesis: a folder of transcripts with no structure validates nothing, and a team that cannot point from a feature decision back to specific evidence is guessing with extra steps.
Rob Fitzpatrick's point is that the hardest part of customer conversations is not finding people, it is asking questions that produce usable data (The Mom Test). Synthesis inherits the same failure mode. If your notes contain "would be great if you built X" and nothing about what the person actually did last Tuesday, no amount of clustering will turn that into a decision. Good synthesis starts by refusing to process bad evidence.
The method below takes raw transcripts to a one-page problem map in roughly a day of focused work for a batch of five to ten interviews, the batch size the Rock Center suggests per persona (HBS Rock Center). It is deliberately mechanical, because the mechanical parts are the ones teams skip.



