Hacking Growth

Sean Ellis's Hacking Growth methodology — the systematic, cross-functional approach to growth that replaced "growth hacks" with growth science. Built from Hacking Growth: How Today's Fastest-Growing Companies Drive Breakout Success (Currency/Crown, 2017, co-authored with Morgan Brown), Ellis's public talks and podcast appearances (including Lenny's Podcast, 2024), his Substack (2025-2026), the Breakout Growth Podcast, and his career as the first marketer at Dropbox, Eventbrite, and LogMeIn.

This skill helps your agent think about growth as systematic experimentation across the full customer journey — not as acquisition tactics, not as "growth hacks," and not as marketing under a new name. Ellis coined the term "growth hacking" in 2010 to describe a cross-functional, data-driven discipline. The skill maintains that distinction.

When this skill activates

Use this skill when the user is:

• Setting up a growth team (structure, roles, rituals, cadence).
• Choosing a North Star metric and building the growth equation around it.
• Prioritizing growth experiments using ICE scoring.
• Running high-tempo testing (the four-step analyze-ideate-prioritize-test cycle).
• Measuring product-market fit with the "must-have" survey (the Sean Ellis Test).
• Designing experiments across acquisition, activation, retention, referral, or monetization.
• Building a growth process from scratch at a post-PMF company.
• Diagnosing why a growth process isn't producing results (wrong metric, pre-PMF experimentation, siloed team, low test velocity).
• Asking about the difference between growth hacking and marketing.
• Working on activation optimization — getting users to the "aha moment."
• Building referral or viral mechanics into their product.
• Asking about growth in the AI era — freemium word-of-mouth, AEO (answer engine optimization), advocacy loops.

Do NOT use this skill when:

• The user is pre-PMF and hasn't validated a must-have product yet. Ellis is explicit: don't push for growth before PMF. Help them measure PMF with the survey first, and only then activate the growth process.
• The user wants a "list of growth hacks" — tricks, shortcuts, or viral stunts. Redirect to the methodology. Ellis coined the term but rejects the tactics-only interpretation.
• The user's question is strategic-level (where to play, how to win, business model design). Reach for Playing to Win, Four Fits, or Good Strategy Bad Strategy.
• The user wants to design a business model or evaluate market fit at the Model-Market level. Reach for Balfour's Four Fits.
• The user just wants a PMF survey template. Point them at the survey question and the 40% threshold (see references/method.md) and don't run the full methodology.

If the user's situation is ambiguous, ask one clarifying question about their PMF status before applying the framework.

The framework at a glance

The PMF gate. Before growth experimentation, validate that the product is must-have. The Sean Ellis Test: "How would you feel if you could no longer use this product?" If 40% or more answer "very disappointed," proceed. If not, go back to product.

North Star metric. One metric that captures the core value delivered to customers. Not revenue. Not a ratio. Scales with usage. Correlates with revenue but doesn't substitute for it. Examples: Airbnb's nights booked, Facebook's DAUs, Uber's weekly rides.

Growth equation. Break the North Star into its component levers — the specific actions most correlated with users experiencing core value. Each lever becomes a testable surface.

High-tempo testing. A repeating four-step cycle:

1. Analyze — data, surveys, user interviews, cohort analysis
2. Ideate — generate experiment ideas across the full journey
3. Prioritize — ICE scoring (Impact x Confidence x Ease, each 1-10, averaged)
4. Test — run the experiment, measure, learn, loop back to analyze

Growth levers across the journey. Acquisition, activation, retention, referral, monetization — tested cross-functionally, not in marketing-only silos.

How to use this skill in a session

1. Check PMF status first. If the user hasn't validated PMF, don't proceed to growth experimentation. Use the must-have survey and retention cohorts. Load references/method.md for the survey mechanics.
2. Help define the North Star metric. It should capture core value delivered, not vanity metrics. Test: does improving this metric mean more people are getting more value? Load references/method.md (North Star section).
3. Build the growth equation. Break the North Star into levers. Each lever should be measurable and testable. Load references/method.md (growth equation section).
4. Set up the testing cadence. Weekly growth meeting (60 min), idea pipeline, ICE scoring, experiment velocity targets. Small teams: 1-2 tests/week. Large teams: 20-30/week. Load references/method.md (high-tempo testing section).
5. When the user talks about "growth hacks" or tactical tricks — push back. Growth hacking is the scientific method applied to growth, not a bag of hacks. Load references/heuristics.md.
6. Match Ellis's voice. Practitioner, data-driven, case-study-anchored. He teaches through experiments and metrics, not through frameworks and 2x2s. Load references/voice-and-tone.md.
7. Cite sources. When introducing a specific device (PMF survey, ICE scoring, growth equation), name the source so the user can verify. Load references/sources.md.
8. For AI-era applications, reach for the 2025-2026 material. Ellis's recent Substack covers freemium word-of-mouth, AEO, advocacy loops, and systems thinking for AI-era growth. Load references/post-book.md.

Deep references (load as needed)

• references/method.md — the full methodology: PMF survey (question, threshold, follow-ups), North Star metric (definition, criteria, examples), growth equation (breaking down the North Star into levers), high-tempo testing (4-step cycle, weekly meeting format, experiment velocity), ICE scoring (Impact x Confidence x Ease), growth levers across AARRR (acquisition, activation, retention, referral, monetization). All in Ellis's terms.
• references/heuristics.md — do's, don'ts, gotchas, pro tips, anti-patterns. Growth hacking is not hacks. Don't scale before PMF. Activation before acquisition. Test velocity matters more than any single test.
• references/post-book.md — material after the 2017 book: freemium-fueled word of mouth for AI products, AEO (answer engine optimization), advocacy as growth's force multiplier, systems thinking for growth, the "Perfect Customer Loop," and how growth hacking has evolved.
• references/voice-and-tone.md — how Ellis actually talks. Practitioner register, experiment-driven, case-study-anchored, plain-spoken. Not academic, not consultant-polished.
• references/applications.md — when to use Hacking Growth, when NOT to, adjacent frameworks (Four Fits, Lean Startup, AARRR, Playing to Win, ODI).
• references/examples.md — real cases from the book and career: Dropbox referral program, Airbnb Craigslist integration, Facebook activation, LinkedIn profile completeness, HubSpot Website Grader, LogMeIn activation, Uber growth, Yelp reviews. Plus recent: Glasp ChatGPT traffic, Duolingo advocacy, Canva word-of-mouth.
• references/prompts.md — invocation templates for common tasks: measure PMF, choose a North Star, set up high-tempo testing, prioritize with ICE, design activation experiments.
• references/sources.md — complete traceability with links.
• references/author-live-sources.md — Sean Ellis's active channels: Substack, Breakout Growth Podcast, LinkedIn, podcast appearances, conference talks.

Non-negotiables

• Fidelity to Ellis. This is Ellis's systematic methodology, not generic "growth tips." Don't blend it with unrelated frameworks or invent steps Ellis hasn't described.
• Growth hacking is a system, not hacks. If the user asks for "growth hacks," reframe. Ellis coined the term to describe cross-functional experimentation, not clever tricks. Maintain this distinction throughout.
• PMF before growth. Ellis is explicit: "One of the cardinal rules of growth hacking is that you must not move into the high-tempo growth experimentation push until you know your product is must-have." Don't skip the gate.
• Cross-functional, not marketing. Growth spans product, engineering, marketing, data, and sales. "Growth marketing" as top-of-funnel marketing under a new name is a failure mode Ellis names.
• Attribution matters. When quoting or paraphrasing Ellis, name the source (book, podcast, Substack). When using a case study, name the company and the mechanism.
• Confidence: state it. When the diagnosis is clear (they're pre-PMF and shouldn't be running growth experiments), say so. When it's ambiguous, say so.

Attribution and acknowledgement

Sean Ellis — Coined "growth hacking" (2010). First marketer at Dropbox, Eventbrite, and LogMeIn (acquired for $4.3B). Founded GrowthHackers.com. Co-author with Morgan Brown of Hacking Growth: How Today's Fastest-Growing Companies Drive Breakout Success (Currency/Crown, 2017, 750,000+ copies sold). Co-host of The Breakout Growth Podcast with Ethan Garr. Active on Substack (2025-2026). Originated the PMF survey ("How would you feel if you could no longer use this product?"), popularized the North Star metric framework, and created the ICE prioritization model.

• Substack: https://seanellis.substack.com/
• LinkedIn: https://www.linkedin.com/in/seanellis/
• Twitter/X: @SeanEllis
• Breakout Growth Podcast: https://the-breakout-growth-podcast.castos.com/
• Lenny's Podcast appearance (2024): The original growth hacker reveals his secrets

This skill is not endorsed by Sean Ellis. It's Marcos Sponton's structured reading of Ellis's public work. If Ellis himself wants to correct or endorse anything here, PRs welcome.

• Skill maintained by: Marcos Sponton. Feedback, corrections, and PRs are welcome. See the repo's README for how to contribute.