The Sean Ellis Test asks whether your product is a must-have for a meaningful slice of users — not whether people like your landing page or clicked an ad once.

How it works

Survey users who have experienced the product recently — typically within the last two weeks and after enough usage to form an opinion. The core question: How would you feel if you could no longer use [product]? Options usually range from “very disappointed” to “not disappointed.”

Teams often look for roughly 40% or more answering “very disappointed” among that qualified cohort. Below that threshold, many founders pause paid acquisition and dig into who actually gets value, why others churn, and what job the product truly owns.

It is one input, not a law. Segment by persona: a niche power user group can score high while the broader market still does not care.

Why it matters

• Founders: Run it before scaling marketing. A low score points you toward product work, not bigger ad budgets.
• Investors: Useful in seed diligence when revenue is thin but engagement exists. They pair it with retention curves and qualitative customer calls.

Common mistake

Surveying everyone who signed up, including people who never activated. That dilutes the signal and makes PMF look worse — or better — than reality.

Related ideas

• Product-market fit and retention cohorts
• Beachhead market
• Net revenue retention as a later-stage health check