Rule of Seven
Also known as: Pattern Threshold, Interview Sufficiency
A qualitative threshold suggesting that a pattern heard from approximately seven independent sources is likely to reflect a real market signal.
Full Definition
The Rule of Seven is not a statistical standard — it is a practical guideline for when a qualitative pattern becomes hard to explain away as coincidence or selection bias. Independence is the key variable: seven people from the same institution or referred by the same contact count as one cluster, not seven independent data points. The Rule of Seven applies in both directions — you don't need 50 interviews to identify a real pattern, but you cannot make confident decisions from two interviews no matter how compelling.
Example
A team hears the same workflow problem described unprompted by seven clinicians from different institutions, different specialties, and different geographies. By the Rule of Seven, this is a signal worth acting on.