# Growth Experiment Engine

> Design and run growth experiments for user acquisition, activation, retention, and viral loops. Use when planning referral programs, optimizing conversion funnels, designing viral mechanics, running A/B tests on growth levers, measuring CAC/LTV, or building product-led growth loops. Covers experiment design, viral coefficient optimization, referral program design, activation funnel optimization, and growth metric frameworks.

- Skill: `nickgallick/growth-experiment-engine` (Agent Skill, multi-file: 5 files)
- Install (CLI): `npx skillmds add nickgallick/growth-experiment-engine`
- Raw SKILL.md: https://api.skillmd.com/api/skills/nickgallick/growth-experiment-engine/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Marketing & Growth
- Author: nickgallick (https://skillmd.com/u/nickgallick)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/nickgallick/growth-experiment-engine

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# Growth Experiment Engine

Systematic framework for designing, running, and measuring growth experiments. Not marketing theory — specific experiment designs with measurement criteria.

## Growth Model → references/growth-model.md
North Star metric, growth equation, funnel stages, leading indicators.

## Viral Loops → references/viral-loops.md
Referral program design, viral coefficient (K-factor), invite mechanics, sharing triggers, network effects.

## Activation Funnel → references/activation-funnel.md
New user → activated user optimization. Onboarding experiments, time-to-value reduction, aha moment identification.

## Experiment Framework → references/experiment-framework.md
How to design, run, and measure growth experiments. Hypothesis format, sample size, duration, statistical significance.

## Workflow

1. Define the growth bottleneck (acquisition? activation? retention? referral?)
2. Read the relevant reference file
3. Design 3-5 experiments targeting the bottleneck
4. Prioritize by ICE score (Impact × Confidence × Ease)
5. Run experiments sequentially (not all at once)
6. Measure, learn, iterate

## Arena Growth Levers
- **Acquisition:** Community channels (Reddit, HN, Discord), SEO, word-of-mouth
- **Activation:** First challenge entered, first result viewed
- **Retention:** Daily challenges, streaks, ELO progression
- **Referral:** Shareable results, embeddable leaderboard widgets, "challenge a friend"
- **Revenue:** Streak freezes, premium features, tournament entry fees