growth-loops（增长循环）

Growth Loops

Design and optimize self-reinforcing growth systems using Reforge methodology—shift from linear funnels to compounding loops where outputs become inputs for sustainable, defensible growth.

When to Use This Skill

Use this skill when you need to:

• Analyze your current growth model and identify if you have a loop or funnel
• Design a growth loop for a new product or feature
• Diagnose why growth isn't compounding despite acquisition efforts
• Identify the right loop type for your business model
• Optimize loop velocity to accelerate growth
• Build multiple loops that feed each other
• Present growth strategy to investors or leadership
• Audit retention's impact on your growth system

This skill is particularly valuable for:

• Growth leaders and PMs designing growth strategy
• Founders building sustainable acquisition models
• Marketing leaders moving beyond paid-only growth
• Product teams embedding growth into the product
• Investors evaluating company growth potential
• Startups seeking capital-efficient growth

Methodology Foundation

Sources:

• Brian Balfour - "Growth Loops are the New Funnels" (Reforge)
• Reforge Growth Series curriculum
• Kevin Kwok - "The Arc of Collaboration"

Core Principle: Growth loops are closed systems where outputs from one cycle become inputs for the next, creating compounding effects over time. Unlike funnels, loops don't require constant external input to maintain output.

"Loops are closed systems where the inputs through some process generates more of an output that can be reinvested in the input." — Brian Balfour

What Claude Does vs What You Decide

What This Skill Does

When invoked, I will guide you through growth loop design and optimization:

1. Assess current state - Determine if you have loops or funnels
2. Identify your core loop - Find the primary mechanism driving growth
3. Map loop components - Input → Action → Output → Feedback
4. Diagnose friction points - Where the loop breaks or slows
5. Measure loop health - Key metrics that matter
6. Optimize velocity - Accelerate cycle time and volume
7. Design secondary loops - Build compound growth systems
8. Create implementation plan - Prioritized improvements

How to Use

Provide information about your business and growth:

Example prompts:

• "Analyze our growth model and identify if we have true loops"
• "Design a viral loop for our collaboration tool"
• "Why isn't our growth compounding despite high acquisition?"
• "What type of growth loop fits our SaaS business?"
• "Help me optimize our referral program as a loop"
• "Audit our growth strategy for defensibility"

Information that helps:

• Your product and value proposition
• Current acquisition channels
• Retention and engagement metrics
• Unit economics (CAC, LTV, payback)
• User actions that create value
• Any existing referral or viral mechanics
• Content or UGC already being created

Instructions

Understanding the Paradigm Shift

The Funnel Problem

Traditional growth thinking:

Awareness → Interest → Consideration → Purchase → (end)
     ↓          ↓           ↓            ↓
   Drop      Drop        Drop         Drop

Why funnels plateau:

• Require constant new input to maintain output
• No compounding effect
• Channels commoditize (CAC rises over time)
• Easily replicated by competitors

The Loop Solution

Growth loop thinking:

    ┌─────────────────────────────────────┐
    │                                     │
    ▼                                     │
New User → Action → Output → Distribution ─┘
                      │
                      └─→ (Attracts more new users)

Why loops compound:

• Output becomes input for next cycle
• Growth accelerates over time
• Creates defensible competitive advantage
• Can decrease CAC as loop strengthens

The Four Types of Growth Loops

Type 1: Viral/Referral Loops

Mechanism: Users invite other users who invite more users.

New User → Experiences Value → Invites Others → New Users Sign Up → Repeat

Best for:

• Collaboration tools (Slack, Zoom, Notion)
• Social products (Facebook, TikTok)
• Products with network effects
• Consumer apps with sharing incentive

Key metrics:

Optimization levers:

• Reduce friction in invitation process
• Increase invitation incentive (both sides)
• Shorten time to value (faster "aha" moment)
• Improve targeting (invite right people)
• Make sharing natural to product use

Type 2: User-Generated Content (UGC) Loops

Mechanism: Users create content that attracts new users who create more content.

User Creates Content → Content Indexed/Distributed → New Users Discover → Sign Up → Create Content → Repeat

Best for:

• Professional networks (LinkedIn)
• Review platforms (Yelp, G2)
• Community platforms (Reddit, Pinterest)
• Marketplaces (Airbnb, Etsy)

Key metrics:

Optimization levers:

• Lower content creation friction
• Improve content templates/prompts
• Optimize content for SEO/feeds
• Incentivize quality content
• Distribute across more channels

Type 3: Paid Marketing Loops

Mechanism: Revenue funds acquisition of customers who generate more revenue.

Ad Spend → Customer Acquisition → Revenue Generation → Reinvest in Ads → Repeat

Best for:

• E-commerce with strong margins
• SaaS with fast payback periods
• Products with high LTV
• Transactional businesses

Key metrics:

Requirements for loop to work:

• LTV > CAC (profit to reinvest)
• Sustainable payback period
• Capital available for investment
• Marginal efficiency doesn't collapse

Optimization levers:

• Increase LTV (retention, expansion revenue)
• Decrease CAC (creative, targeting, conversion)
• Shorten payback (pricing, onboarding)
• Improve capital efficiency

Type 4: Sales Loops

Mechanism: Customer success creates reference customers that help close more deals.

Close Deal → Customer Success → Case Study/Reference → Credibility → Close More Deals → Repeat

Best for:

• Enterprise SaaS
• High-ticket B2B services
• Consultancies and agencies
• Complex sale products

Key metrics:

Optimization levers:

• Accelerate customer onboarding
• Define and measure success clearly
• Systematize case study production
• Train sales on storytelling
• Segment by successful customer profile

Why Retention Powers Every Loop

"Retention is the foundation of growth." — Brian Balfour

Without retention, loops break:

Retention amplifies loops:

• Retained users make more invitations over time
• Retained users create more content
• Retained users have higher LTV
• Retained customers become better references

Before optimizing any loop, ensure:

• Week 1 retention > 40%
• Month 1 retention > 25%
• Core action repeated regularly
• Users reaching "aha" moment

Designing Your Growth Loop

Step 1: Identify Your Value Action

What single action, when taken by users, creates the most value?

Step 2: Find the Byproduct

What does the value action naturally produce that could attract new users?

Step 3: Map the Complete Loop

INPUT: What triggers the loop?
       └─→ ACTION: What does the user do?
                  └─→ OUTPUT: What does the action create?
                             └─→ DISTRIBUTION: How do new users discover?
                                              └─→ CONVERSION: How do they become input?
                                                             └─→ [Back to INPUT]

Step 4: Measure Each Step

For each step, define:

• Volume: How many users/actions?
• Conversion: What % proceed to next step?
• Velocity: How quickly does it happen?

Step 5: Find the Constraint

The slowest or leakiest step determines loop speed.

Questions to ask:

• Where do we lose the most volume?
• Where does the loop take the longest?
• What step has the lowest conversion?
• What assumption are we making that might be wrong?

Loop Optimization Framework

The Loop Velocity Equation

Loop Velocity = Volume × Efficiency × Frequency

• Volume: How many users enter the loop
• Efficiency: What % complete the full loop
• Frequency: How often the loop cycles

To accelerate growth, improve any factor:

Prioritization Matrix

Building Multiple Loops

Best-in-class companies run multiple interconnected loops:

LinkedIn Example:

1. Profile SEO Loop (UGC)

- Create profile → Rank in Google → Sign up → Create profile

1. Connection Viral Loop

- Connect → Invitations → Sign up → Connect

1. Content Feed Loop (UGC)

- Post → Feed distribution → Engagement → More posting

1. Job Posting Loop (Paid/UGC hybrid)

- Post job → Candidates apply → Value → More jobs posted

Key insight: Loops can feed each other:

• Profile loop brings users who create content
• Content loop increases engagement for profile loop
• Job loop monetizes while reinforcing value

Growth Loop Audit

Use this framework to assess your current state:

Audit Questions

1. What is our primary growth loop today?

- Can you draw it as a closed loop? - Or is it actually a funnel (linear, no feedback)?

1. What is our loop velocity?

- How long does one cycle take? - How many cycles per month?

1. What is the primary friction point?

- Where does the loop break most often? - What step has lowest conversion?

1. What is our retention rate?

- Is retention strong enough to power the loop? - Where do we lose users before they can fuel the loop?

1. Are we measuring loop health?

- Do we track cycle time? - Do we track loop-specific metrics vs. vanity metrics?

1. Could we add a secondary loop?

- What other byproducts could attract users? - What adjacent loop types fit our model?

1. What would 10x our loop velocity?

- If we had to accelerate dramatically, what would we change? - What bold bets would we make?

Examples

Example 1: Designing a Viral Loop for a Project Management Tool

Context: B2B project management SaaS with strong retention but growth dependent on paid ads. CAC rising, need sustainable growth channel.

Analysis:

Current State (Funnel):

Google Ads → Landing Page → Trial → Paid
    ↓            ↓           ↓
  70%          65%         75%
  drop         drop        drop

• No loop: requires constant ad spend
• CAC: $180, rising 15% annually
• LTV: $540 (3-year average)
• Loop opportunity: product requires team collaboration

Designed Loop (Viral):

New User Signs Up
       │
       ▼
Creates Project + Invites Team (natural to use product)
       │
       ▼
Teammates Receive Invite (see product value in email)
       │
       ▼
25% Sign Up (free tier, no friction)
       │
       ▼
New Users Create Projects + Invite Their Teams
       │
       └─────────────► [Loop repeats]

Loop Metrics:

Optimization Plan:

1. Increase invitation rate (15% → 40%)

- Move "invite team" to onboarding flow (required step) - Add empty state prompts ("This project is lonely...") - Create @mention that triggers invitation

1. Increase invite volume (2 → 5)

- Import from Slack/email contacts - Suggest teammates based on company domain - "Invite all" button for groups

1. Improve invite conversion (12% → 25%)

- Personalize invite email (project name, inviter name) - Show preview of project activity in email - One-click accept (no form to start)

1. Shorten cycle time (14 days → 5 days)

- Trigger invite prompt after first milestone, not after 7 days - Daily digest showing team activity (creates FOMO)

Projected Impact:

• K-factor improvement: 0.04 → 0.5
• Reduces dependence on paid by 40%
• CAC drops as organic grows

Example 2: Building a UGC Loop for a B2B Review Platform

Context: Software review site competing with G2 and Capterra. Need more reviews to rank in search, need traffic to get more reviewers. Classic chicken-and-egg.

Designed Loop:

User Writes Review
       │
       ▼
Review Published (optimized for "[Software] review" keywords)
       │
       ▼
Review Ranks in Google
       │
       ▼
Searcher Finds Review, Visits Site
       │
       ▼
20% Sign Up to Write Their Own Review
       │
       ▼
New User Writes Review
       │
       └─────────────► [Loop repeats]

Loop Metrics:

Optimization Plan:

1. Increase review creation (500 → 2,000)

- Review incentive program ($10 gift card) - "Review swap" with software vendors - LinkedIn outreach to verified users - Post-NPS trigger: "Score 9-10? Write a public review"

1. Improve SEO ranking (5% → 25%)

- Structured data for reviews (schema markup) - Internal linking strategy (category → product → reviews) - Review template that naturally includes keywords - Freshness: encourage review updates

1. Increase traffic → signup (2% → 5%)

- "Write your review" CTA on every review page - Show "reviewer badges" (status incentive) - Personalized prompt: "You use [Software]? Share your experience"

1. Increase signup → review (10% → 30%)

- Pre-fill review with software they indicated using - Review wizard (guided questions, not blank page) - Progress bar showing completion - Instant badge/reward upon submission

Secondary Loop (Viral):

User Writes Review → Shares on LinkedIn → Colleagues See → Sign Up to Write

• Encourage sharing with "Add to LinkedIn profile" feature
• Badge image optimized for social sharing

Compound Effect:

• Year 1: 2,000 reviews, 50K organic traffic
• Year 2: 8,000 reviews, 200K organic traffic
• Year 3: 30,000 reviews, 1M organic traffic
• Each review compounds SEO value indefinitely

Checklists & Templates

Growth Loop Design Canvas

GROWTH LOOP DESIGN CANVAS
═══════════════════════════════════════════════════════════

PRODUCT: ____________________
LOOP TYPE: [ ] Viral  [ ] UGC  [ ] Paid  [ ] Sales

────────────────────────────────────────────────────────────

1. VALUE ACTION
What action creates value for users?
____________________________________________________

2. BYPRODUCT
What does this action produce that could attract new users?
____________________________________________________

3. DISTRIBUTION
How will new users discover this byproduct?
[ ] Search/SEO
[ ] Social sharing
[ ] Direct invitation
[ ] Paid amplification
[ ] Word of mouth

4. CONVERSION
How do discoverers become new users?
____________________________________________________

────────────────────────────────────────────────────────────

LOOP DIAGRAM

    ┌──────────────────────────────────────────┐
    │                                          │
    ▼                                          │
[INPUT]                                        │
    │                                          │
    └──► [ACTION] ──► [OUTPUT] ──► [DISTRIBUTION]

────────────────────────────────────────────────────────────

KEY METRICS

| Step | Metric | Current | Target |
|------|--------|---------|--------|
| Input | ______________ | _____ | _____ |
| Action | ______________ | _____ | _____ |
| Output | ______________ | _____ | _____ |
| Distribution | ______________ | _____ | _____ |
| Conversion | ______________ | _____ | _____ |

Cycle time: _____ days
Viral coefficient (if applicable): _____

────────────────────────────────────────────────────────────

CONSTRAINT ANALYSIS
What's the biggest bottleneck in this loop?
____________________________________________________

Top 3 improvements to accelerate the loop:
1. ____________________________________________________
2. ____________________________________________________
3. ____________________________________________________

Loop Health Dashboard Template

WEEKLY LOOP HEALTH METRICS
═══════════════════════════════════════════════════════════

Loop: [Name]                     Week of: [Date]

────────────────────────────────────────────────────────────

VELOCITY METRICS
                        This Week   Last Week   Trend
Loop cycles completed:  _________   _________   ↑/↓/→
Average cycle time:     _________   _________   ↑/↓/→
Volume entering loop:   _________   _________   ↑/↓/→

────────────────────────────────────────────────────────────

STEP CONVERSION RATES
                        This Week   Target      Status
Step 1 (Input→Action):  _________%  _________%  🟢/🟡/🔴
Step 2 (Action→Output): _________%  _________%  🟢/🟡/🔴
Step 3 (Output→Dist):   _________%  _________%  🟢/🟡/🔴
Step 4 (Dist→Conv):     _________%  _________%  🟢/🟡/🔴

────────────────────────────────────────────────────────────

RETENTION (Loop Foundation)
                        This Week   Target      Status
Week 1 retention:       _________%  40%+        🟢/🟡/🔴
Month 1 retention:      _________%  25%+        🟢/🟡/🔴
Core action frequency:  _________   _________   🟢/🟡/🔴

────────────────────────────────────────────────────────────

CONSTRAINT THIS WEEK
Biggest bottleneck: _________________________________
Action being taken: _________________________________

────────────────────────────────────────────────────────────

LOOP COMPOUNDING
Organic/loop-driven growth %:    _________%
Paid-driven growth %:            _________%
Target organic %:                _________%

Loop Type Selection Guide

WHICH LOOP TYPE FITS YOUR BUSINESS?
═══════════════════════════════════════════════════════════

Answer these questions to identify your primary loop:

1. DOES YOUR PRODUCT REQUIRE MULTIPLE USERS TO FUNCTION?
   [ ] Yes → Strong viral loop potential
   [ ] No → Consider UGC or Paid loops

2. DO USERS CREATE CONTENT AS PART OF USING YOUR PRODUCT?
   [ ] Yes → Strong UGC loop potential
   [ ] No → Consider Viral or Paid loops

3. WHAT ARE YOUR UNIT ECONOMICS?
   [ ] LTV:CAC > 5:1, payback < 6 months → Paid loop viable
   [ ] LTV:CAC 3-5:1, payback 6-12 months → Paid loop possible
   [ ] LTV:CAC < 3:1, payback > 12 months → Need organic loop first

4. IS YOUR SALE COMPLEX/HIGH-TOUCH?
   [ ] Yes, enterprise/high-ticket → Sales loop
   [ ] No, self-serve → Viral, UGC, or Paid loop

5. DO CUSTOMERS GET MEASURABLE RESULTS?
   [ ] Yes, with clear metrics → Sales loop reinforcement
   [ ] No, value is qualitative → Harder sales loop, try others

────────────────────────────────────────────────────────────

RECOMMENDED PRIMARY LOOP: ____________________

RECOMMENDED SECONDARY LOOP: ____________________

Skill Boundaries

What This Skill Does Well

• Structuring strategic analysis
• Identifying market opportunities
• Creating strategic frameworks
• Synthesizing competitive data

What This Skill Cannot Do

• Replace market research
• Guarantee strategic success
• Know proprietary competitor info
• Make executive decisions

References

Primary Sources:

• Balfour, Brian. "Growth Loops are the New Funnels." Reforge.
• Reforge Growth Series curriculum.
• Kwok, Kevin. "The Arc of Collaboration."

Additional Resources:

• Ellis, Sean. "Hacking Growth."
• Balfour, Brian. "Why Product-Market Fit Isn't Enough." Reforge.
• Reforge. "Retention Playbook."
• Chen, Andrew. "The Cold Start Problem."

Related Skills

• product-led-growth - Self-serve growth strategies
• funnel-optimization - Improving linear conversion
• viral-mechanics - Designing viral features
• retention-strategy - Foundation for all loops
• unit-economics - CAC, LTV, payback analysis
• content-strategy - Powering UGC loops
• referral-programs - Structured viral mechanics