Conversion Rate Optimization - A/B testing methodology, landing page optimization, form design, statistical significance, and funnel analysis.
Built as a no-fluff execution skill for systematic conversion rate optimization.
Structure: Core CRO fundamentals first. Advanced testing in dedicated sections. AI/ML optimization in clearly labeled "Optional: AI / Automation" sections.
1. ANALYZE → Identify conversion problems (data + qualitative)
2. HYPOTHESIZE → Form testable hypotheses
3. PRIORITIZE → Score by impact/effort (ICE/PIE)
4. TEST → Run A/B tests with statistical rigor
5. LEARN → Document results, iterate
6. IMPLEMENT → Roll out winners, test next
| Page Type | Poor | Average | Good | Great |
|---|---|---|---|---|
| Landing page | <1% | 2-3% | 4-5% | >6% |
| Checkout | <40% | 50-60% | 65-75% | >80% |
| Form completion | <20% | 30-40% | 45-55% | >60% |
| Add to cart | <3% | 5-8% | 9-12% | >15% |
Note: Benchmarks vary significantly by industry. Use as directional only.
Every landing page needs these elements visible without scrolling:
| Element | Requirement | Common Issues |
|---|---|---|
| Headline | Clear value proposition | Vague, company-focused |
| Subheadline | Specific benefit or outcome | Missing or weak |
| Hero image/video | Relevant, shows outcome | Stock photos, irrelevant |
| CTA | Prominent, action-oriented | Hidden, generic text |
| Trust signal | Logo strip, rating, or stat | Missing entirely |
[Outcome] + [Timeframe/Ease] + [Without Pain Point]
Examples:
"Get 10 qualified leads per week without cold calling"
"File your tax return in 15 minutes with expert review"
"Double your email conversions without hiring a copywriter"
| Do | Don't |
|---|---|
| "Start Free Trial" | "Submit" |
| "Get My Quote" | "Click Here" |
| "Book My Demo" | "Learn More" (bottom of funnel) |
| "Download the Guide" | "Send" |
CTA Button Optimization:
STRONGEST TRUST SIGNALS (use at least 3):
├─ Customer logos (recognizable brands)
├─ Review score (4.5+ stars with count)
├─ Security badges (SSL, payment, compliance)
├─ Money-back guarantee
└─ Phone number visible
SUPPORTING TRUST SIGNALS:
├─ Customer testimonials (with photo, name, company)
├─ Case study snippets (specific metrics)
├─ "As seen in" media logos
├─ Team photos (for services)
├─ Live chat widget
└─ Physical address (for services)
| Rule | Why | Impact |
|---|---|---|
| Minimum fields | Every field = friction | -10% CVR per field (approx) |
| Email first | Captures partial submissions | +15-30% lead capture |
| Labels above fields | Faster scanning | +10% completion |
| Single column | Easier flow | +5-10% completion |
| Inline validation | Catch errors early | +22% completion |
| Priority | Field | When Required |
|---|---|---|
| 1 | Always | |
| 2 | Name | If personalization needed |
| 3 | Company | B2B only |
| 4 | Phone | Sales-ready leads only |
| 5 | Job title | Enterprise targeting |
| 6+ | Everything else | Gate behind progressive profiling |
Step 1: Low commitment (email)
├─ "What's your email?"
├─ Progress indicator: 1 of 3
└─ CTA: "Continue"
Step 2: Qualifying info
├─ Company size / Industry
├─ Progress indicator: 2 of 3
└─ CTA: "Almost there"
Step 3: Contact info
├─ Name / Phone (optional)
├─ Progress indicator: 3 of 3
└─ CTA: "Get My [Deliverable]"
Multi-step benefits:
IF we [change/add/remove X]
THEN [metric] will [increase/decrease] by [estimate]
BECAUSE [reasoning based on data/research]
Example:
IF we add customer logos to the hero section
THEN form conversion will increase by 15%
BECAUSE trust signals reduce perceived risk for new visitors
Minimum sample size formula (simplified):
n = (16 × p × (1-p)) / MDE²
Where:
- n = sample per variant
- p = baseline conversion rate
- MDE = minimum detectable effect (e.g., 0.10 for 10% lift)
Example:
Baseline CVR: 3% (0.03)
MDE: 20% relative lift (looking for 3.6% or higher)
n = (16 × 0.03 × 0.97) / (0.006)²
n ≈ 12,933 per variant
Total traffic needed: ~26,000 visitors
Quick reference:
| Baseline CVR | 10% MDE | 20% MDE | 30% MDE |
|---|---|---|---|
| 1% | 63,000 | 15,800 | 7,000 |
| 3% | 20,700 | 5,200 | 2,300 |
| 5% | 12,200 | 3,050 | 1,350 |
| 10% | 5,800 | 1,450 | 650 |
Per variant. Multiply by 2 for total traffic needed.
Requirements for valid test:
| Factor | Score (1-10) | Description |
|---|---|---|
| Impact | How much will this move the metric? | |
| Confidence | How sure are we this will work? | |
| Ease | How easy is this to implement? | |
| ICE Score | (Impact + Confidence + Ease) / 3 |
ICE Score interpretation:
STEP 1: Map your funnel
Page Visit → Key Action → Form Start → Form Complete → Confirmation
STEP 2: Measure drop-off at each step
├─ Page Visit to Key Action: ___% (bounce rate inverse)
├─ Key Action to Form Start: ___%
├─ Form Start to Complete: ___%
└─ Complete to Confirmation: ___%
STEP 3: Identify biggest drop-off
Biggest percentage drop = highest priority to fix
STEP 4: Diagnose root cause
├─ High bounce? → Relevance, load speed, messaging
├─ Low engagement? → Content, CTA visibility
├─ Form abandonment? → Form friction, trust
└─ Checkout drop? → Pricing, shipping, trust
| Funnel Stage | Micro-Conversions to Track |
|---|---|
| Awareness | Scroll depth, time on page, video views |
| Interest | CTA hover, tab/section views, resource clicks |
| Consideration | Pricing page visit, comparison page, demo video |
| Decision | Form start, add to cart, checkout start |
| Conversion | Form complete, purchase, signup |
What to look for:
| Load Time | Impact |
|---|---|
| 0-2 seconds | Baseline (optimal) |
| 3 seconds | -7% conversion |
| 5 seconds | -22% conversion |
| 10 seconds | -50%+ conversion |
Source: Google/Akamai research, directional only
| Metric | Good | Needs Improvement | Poor |
|---|---|---|---|
| LCP (Largest Contentful Paint) | <2.5s | 2.5-4s | >4s |
| INP (Interaction to Next Paint) | <200ms | 200-500ms | >500ms |
| CLS (Cumulative Layout Shift) | <0.1 | 0.1-0.25 | >0.25 |
| Action | Impact | Effort |
|---|---|---|
| Compress images | High | Low |
| Enable caching | High | Low |
| Remove unused scripts | Medium | Medium |
| Lazy load below-fold content | Medium | Low |
| Use CDN | High | Medium |
| Optimize fonts | Medium | Low |
| Task | Template | Location |
|---|---|---|
| Landing page audit | Page audit checklist | templates/landing-audit.md |
| A/B test plan | Test hypothesis doc | templates/ab-test-plan.md |
| Form audit | Form optimization | templates/form-audit.md |
| Funnel analysis | Funnel diagnostic | templates/funnel-analysis.md |
| Test prioritization | ICE scoring matrix | templates/ice-scoring.md |
Low conversion rate?
├─ Check page speed first (if >3s, fix that)
├─ Check bounce rate
│ ├─ High bounce (>70%) → Message/audience mismatch
│ └─ Normal bounce → Continue diagnosis
├─ Check scroll depth
│ ├─ Low scroll → Above-fold problem
│ └─ Good scroll → Below-fold CTA/proof issue
├─ Check form analytics
│ ├─ Low form starts → CTA/offer problem
│ └─ High abandonment → Form friction
└─ Check mobile vs desktop
├─ Mobile worse → Mobile UX issues
└─ Same → Universal issue
Form abandonment?
├─ Check which field causes drop-off
├─ Reduce fields to minimum
├─ Add progress indicator
├─ Add inline validation
└─ Test multi-step
Traffic but no clicks?
├─ CTA not visible → Move above fold
├─ CTA not compelling → Test copy
├─ Too many options → Simplify, single CTA
└─ Page too long → Add sticky CTA
Check conversion metrics
Review active tests
Prioritize next tests
Full funnel analysis
Heatmap/recording review
Test performance review
Competitive analysis
| Template | Purpose |
|---|---|
| landing-audit.md | Full landing page audit |
| ab-test-plan.md | A/B test planning |
| form-audit.md | Form optimization checklist |
| funnel-analysis.md | Funnel diagnostic |
| ice-scoring.md | Test prioritization |
| Anti-Pattern | Why It Fails | Instead |
|---|---|---|
| Testing too small changes | Undetectable effect, wasted time | Test big, obvious changes first |
| Stopping tests early | False positives, bad decisions | Run to calculated sample size |
| No hypothesis | Random changes, no learnings | Document hypothesis before test |
| Testing everything at once | Can't isolate what worked | One variable at a time |
| Ignoring mobile | 60%+ traffic is mobile | Mobile-first optimization |
| Copying competitors | Different audience, context | Use for ideas, test your own |
| Only A/B testing | Misses qualitative insights | Combine with user research |
Note: Core CRO fundamentals above work without AI. This section covers optional AI capabilities.
| Tool Type | Use Case | Examples |
|---|---|---|
| AI copy generation | Headline/CTA variants | Claude, GPT, Jasper |
| Personalization | Dynamic content by segment | Optimizely, VWO |
| Predictive testing | Predict winners faster | Evolv AI, Sentient |
| Auto-optimization | Multi-armed bandit | Google Optimize (sunset), VWO |
HAVE thousands of daily conversions?
├─ YES → AI personalization can optimize in real-time
└─ NO → Stick to traditional A/B testing
NEED many variants quickly?
├─ YES → AI copy generation for variant ideation
└─ NO → Human copywriting with hypothesis
HAVE limited traffic?
├─ YES → Qualitative research over testing
└─ NO → Statistical A/B tests