Growth Marketing Glossary

Sean Ellis

/ʃɔn ˈɛlɪs/proper noun

The man who named the discipline — then spent a decade explaining that he meant process, not tricks.

“how would you feel without this product?”very disappointed40% lineclears 40%= PMFthe Sean Ellis test — the bar for product-market fit
Portrait mark — Sean Ellis
Name
Sean Ellis
Coined
Growth hacking (2010)
Key work
Hacking Growth (2017)
Known for
The 40% PMF survey

Forms & parts of speech

Ellis test · proper noun
His product-market-fit survey.
"Run the Ellis test — what share would be very disappointed without us?"

Who he is, in plain terms

Sean Ellis is the growth practitioner who ran early growth at Dropbox, LogMeIn, and Eventbrite, founded GrowthHackers.com, and co-wrote Hacking Growth (2017) with Morgan Brown. He is best known for two things — naming the discipline, and giving it its most-used survey question.

The key ideas

His July 2010 blog post "Find a Growth Hacker for Your Startup" defined the role as "a person whose true north is growth." The Ellis test asks users how they would feel if they could no longer use the product — when 40% or more say "very disappointed," you have a signal of product-market fit worth scaling. And his core process is the high-tempo testing loop: rank ideas, run experiments weekly, keep what moves the North Star metric.

Why he still matters

Every growth team that runs a weekly experiment cadence against a single focus metric is running his playbook. The 40% benchmark remains the most-cited PMF threshold in startup writing, and his insistence that growth work starts AFTER product-market fit is the discipline's most ignored — and most expensive to ignore — rule.

Worked example. A seed-stage SaaS team wants to pour budget into ads. The Ellis sequence says measure first — they survey active users and only 22% would be very disappointed to lose the product. So the budget goes to activation and retention fixes instead of acquisition. Two quarters later the survey crosses 40% and the same ad spend finally compounds instead of leaking.
Failure modes to watch. Reading growth hacking as a bag of tricks rather than a testing process; scaling acquisition before the 40% signal; and chasing experiment volume while the North Star metric sits unmoved.

Synonyms & antonyms

Synonyms

Sean Ellisthe Ellis test

Origin & history

Coined "growth hacking" in his July 26, 2010 blog post "Find a Growth Hacker for Your Startup" on Startup-Marketing.com, after finding "marketer" mis-described the testing-driven role he kept hiring for. The 40% survey emerged from his interim-growth work across dozens of startups.

Etymology: source.

Usage trends

Search interest for this term over the last five years:

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Common questions

Who is Sean Ellis?
The growth practitioner who coined the term growth hacking in 2010, ran early growth at Dropbox and LogMeIn, and co-wrote Hacking Growth.
What is the Sean Ellis test?
A survey asking users how disappointed they would be without the product — 40%+ saying very disappointed signals product-market fit.
What did Ellis mean by growth hacking?
A disciplined, high-tempo experimentation process aimed at one growth metric — not a collection of marketing tricks.

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Resources & people to follow

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Disciplines

Areas of marketing where sean ellis is a core concern:

Sources

  1. trendsGoogle Trends — "sean ellis growth"