Essay · ~10 min read

Interview Sample Size in Qualitative UX Research

Maria Rosala · Nielsen Norman Group (nngroup.com) Free Beginner

The honest answer to 'how many' is not a magic number, it is saturation: you keep going until new interviews stop teaching you anything new. This piece explains that idea plainly and gives a workable starting point (begin with about 5 to 6, then continue until the themes stop shifting), which is exactly the judgment call a founder is trying to make. Treat it as a rule of thumb to sanity-check your gut, not a quota to hit.

• Saturation is the real stopping rule: when the same jobs and pains keep repeating and fresh interviews add nothing, you can trust the pattern.
• Start small (roughly 5 to 6) for a focused, similar group, and add more the moment answers start diverging.
• The number depends on how varied your customers are and how broad your question is, so a wildly mixed audience needs more conversations than a narrow one.