A/B Test Design & Experiment Planning
Concept adapted from OpenClaudia/openclaudia-skills (ab-test-setup).
Process
- Understand what the user wants to test (creative, audience, bidding, landing page)
- Build structured hypothesis using the framework below
- Calculate required sample size and estimated duration
- Recommend platform-specific test setup
- Define success criteria and measurement plan
Hypothesis Framework
Every test must start with a structured hypothesis:
IF we [change/action]
THEN [metric] will [increase/decrease] by [estimated %]
BECAUSE [reasoning based on data or insight]
Example:
IF we replace polished product shots with UGC creator videos
THEN Meta CTR will increase by 25-40%
BECAUSE Andromeda prioritizes diverse creative formats and UGC consistently outperforms polished in 2025-2026 benchmarks
Hypothesis Quality Checklist
Statistical Significance Calculator
Required Sample Size (per variant):
n = (Z_alpha + Z_beta)^2 × 2 × p × (1-p) / MDE^2
Where:
- Z_alpha = 1.96 (for 95% confidence)
- Z_beta = 0.84 (for 80% power)
- p = baseline conversion rate
- MDE = minimum detectable effect (relative %)
Simplified lookup:
| Baseline CVR |
5% MDE |
10% MDE |
20% MDE |
30% MDE |
| 1% |
612,000 |
153,000 |
38,300 |
17,000 |
| 2% |
302,400 |
75,600 |
18,900 |
8,400 |
| 5% |
116,800 |
29,200 |
7,300 |
3,200 |
| 10% |
55,200 |
13,800 |
3,450 |
1,530 |
| 20% |
24,600 |
6,150 |
1,540 |
680 |
Per variant, 95% confidence, 80% power
Test Duration Estimator
Duration = Required Sample Size / Daily Traffic per Variant
Minimum duration: 7 days (capture weekly patterns)
Maximum recommended: 28 days (avoid seasonal drift)
Learning phase: Google 7-14 days, Meta 3-7 days, LinkedIn 7-14 days
Inputs needed:
- Daily impressions or clicks
- Number of variants (2 = A/B, 3+ = multivariate)
- Baseline conversion rate
- Minimum detectable effect desired
Duration Quick Estimates
| Daily Clicks |
2% CVR, 20% MDE |
5% CVR, 20% MDE |
10% CVR, 20% MDE |
| 100 |
189 days |
73 days |
35 days |
| 500 |
38 days |
15 days |
7 days |
| 1,000 |
19 days |
7 days |
4 days* |
| 5,000 |
4 days* |
2 days* |
1 day* |
*Minimum 7 days recommended regardless of sample sufficiency
Platform-Specific Test Setup
Meta Experiments
- Use Ads Manager > Experiments tab (not manual ad set duplication)
- Automatic audience splitting ensures no overlap
- Supported test types: A/B (creative, audience, placement), Holdout, Brand Survey
- Meta's Incremental Attribution (April 2025) provides AI-powered holdout testing for measuring real causal impact
- Budget: split evenly across variants; minimum $100/day per variant recommended
- Duration: 7-14 days typical; Meta auto-determines winner at 95% confidence
Google Experiments
- Campaign Experiments (custom experiments) or Ad Variations
- Create experiment from existing campaign > select experiment type
- Traffic split: 50/50 recommended for fastest results
- Supported: bidding strategy, ad copy, landing page, audience
- Metrics: choose primary metric (conversions, CPA, ROAS) before launch
- Duration: 14-30 days recommended; minimum 2 weeks for bidding tests
LinkedIn A/B Testing
- Built into Campaign Manager for Sponsored Content
- Duplicate ad set with single variable change
- Target: same audience segment with automatic rotation
- Minimum budget: $50/day per variant
- Key metrics: CTR (>0.44% benchmark), CPL, Lead Form CVR (13% benchmark)
- Duration: 14-21 days (LinkedIn's smaller daily volumes require longer tests)
TikTok Split Testing
- Available in TikTok Ads Manager > Create A/B Test
- Test types: targeting, bidding, creative
- Auto-splits audience to avoid contamination
- Minimum 7 days, recommended 14 days
- Budget: minimum $20/day per ad group
- Creative tests: isolate hook (first 2-3 seconds) as the primary variable
- TikTok's enhanced split testing supports modular test variables (targeting, creative, budget, placement) via Smart+ since 2025
What to Test (Priority Order)
High Impact (test first)
- Creative concept (different messaging angles, not just color changes)
- Hook/first 3 seconds (video opening on Meta, TikTok, YouTube)
- Offer structure (pricing, discount type, free trial length)
- Landing page (headline, CTA, form length)
- Bidding strategy (tCPA vs tROAS vs Maximize Conversions)
Medium Impact
- Audience targeting (interest vs lookalike vs broad)
- Ad format (static vs video vs carousel)
- CTA button (Learn More vs Sign Up vs Shop Now)
- Campaign structure (CBO vs ABO, consolidated vs segmented)
Low Impact (test last)
- Ad scheduling (time of day, day of week)
- Device targeting (mobile vs desktop)
- Minor copy variations (word substitutions without concept change)
Common Testing Mistakes to Avoid
- Testing too many variables at once (no clear winner attribution)
- Ending tests too early (before statistical significance)
- Testing during atypical periods (holidays, launches, incidents)
- Comparing unequal time periods
- Not documenting learnings (build institutional knowledge)
- Testing small changes when big changes are needed (optimize vs innovate)
- Ignoring learning phase on automated platforms
Output Format
## A/B Test Plan
### Hypothesis
IF [change]
THEN [metric] will [direction] by [amount]
BECAUSE [reasoning]
### Test Design
| Parameter | Value |
|-----------|-------|
| Platform | [platform] |
| Test Type | [A/B / Multivariate] |
| Variable | [what's being changed] |
| Control | [current state] |
| Variant | [proposed change] |
| Primary Metric | [KPI] |
| Traffic Split | [50/50 / other] |
### Sample Size & Duration
| Metric | Value |
|--------|-------|
| Baseline CVR | [X%] |
| MDE | [X%] |
| Required Sample | [N per variant] |
| Daily Traffic | [N clicks/day] |
| Est. Duration | [X days] |
| Min Duration | 7 days |
### Success Criteria
- Winner declared at 95% confidence
- [Primary metric] improvement of [X%]+ sustained over [Y] days
- No negative impact on [secondary metric]
### Setup Instructions
[Platform-specific step-by-step]
1---2name: ads-test3description: A/B test design and experiment planning for paid advertising. Structured hypothesis framework, statistical significance calculator, test duration estimator, sample size calculator, and platform-specific experiment setup guides (Meta Experiments, Google Experiments, LinkedIn A/B). Use when user says A/B test, split test, experiment design, test hypothesis, statistical significance, sample size, or test duration.4---56# A/B Test Design & Experiment Planning78> Concept adapted from `OpenClaudia/openclaudia-skills` (ab-test-setup).910## Process11121. Understand what the user wants to test (creative, audience, bidding, landing page)132. Build structured hypothesis using the framework below143. Calculate required sample size and estimated duration154. Recommend platform-specific test setup165. Define success criteria and measurement plan1718## Hypothesis Framework1920Every test must start with a structured hypothesis:2122```23IF we [change/action]24THEN [metric] will [increase/decrease] by [estimated %]25BECAUSE [reasoning based on data or insight]2627Example:28IF we replace polished product shots with UGC creator videos29THEN Meta CTR will increase by 25-40%30BECAUSE Andromeda prioritizes diverse creative formats and UGC consistently outperforms polished in 2025-2026 benchmarks31```3233### Hypothesis Quality Checklist34- [ ] Single variable being tested (isolate the change)35- [ ] Specific metric defined (not "performance")36- [ ] Estimated effect size stated (needed for sample size calculation)37- [ ] Timeframe defined38- [ ] Success/failure criteria clear before launch3940## Statistical Significance Calculator4142```43Required Sample Size (per variant):4445n = (Z_alpha + Z_beta)^2 × 2 × p × (1-p) / MDE^24647Where:48- Z_alpha = 1.96 (for 95% confidence)49- Z_beta = 0.84 (for 80% power)50- p = baseline conversion rate51- MDE = minimum detectable effect (relative %)5253Simplified lookup:54```5556| Baseline CVR | 5% MDE | 10% MDE | 20% MDE | 30% MDE |57|-------------|---------|---------|---------|---------|58| 1% | 612,000 | 153,000 | 38,300 | 17,000 |59| 2% | 302,400 | 75,600 | 18,900 | 8,400 |60| 5% | 116,800 | 29,200 | 7,300 | 3,200 |61| 10% | 55,200 | 13,800 | 3,450 | 1,530 |62| 20% | 24,600 | 6,150 | 1,540 | 680 |6364*Per variant, 95% confidence, 80% power*6566## Test Duration Estimator6768```69Duration = Required Sample Size / Daily Traffic per Variant7071Minimum duration: 7 days (capture weekly patterns)72Maximum recommended: 28 days (avoid seasonal drift)73Learning phase: Google 7-14 days, Meta 3-7 days, LinkedIn 7-14 days7475Inputs needed:76- Daily impressions or clicks77- Number of variants (2 = A/B, 3+ = multivariate)78- Baseline conversion rate79- Minimum detectable effect desired80```8182### Duration Quick Estimates8384| Daily Clicks | 2% CVR, 20% MDE | 5% CVR, 20% MDE | 10% CVR, 20% MDE |85|-------------|-----------------|-----------------|-----------------|86| 100 | 189 days | 73 days | 35 days |87| 500 | 38 days | 15 days | 7 days |88| 1,000 | 19 days | 7 days | 4 days* |89| 5,000 | 4 days* | 2 days* | 1 day* |9091*Minimum 7 days recommended regardless of sample sufficiency9293## Platform-Specific Test Setup9495### Meta Experiments96- Use Ads Manager > Experiments tab (not manual ad set duplication)97- Automatic audience splitting ensures no overlap98- Supported test types: A/B (creative, audience, placement), Holdout, Brand Survey99- Meta's Incremental Attribution (April 2025) provides AI-powered holdout testing for measuring real causal impact100- Budget: split evenly across variants; minimum $100/day per variant recommended101- Duration: 7-14 days typical; Meta auto-determines winner at 95% confidence102103### Google Experiments104- Campaign Experiments (custom experiments) or Ad Variations105- Create experiment from existing campaign > select experiment type106- Traffic split: 50/50 recommended for fastest results107- Supported: bidding strategy, ad copy, landing page, audience108- Metrics: choose primary metric (conversions, CPA, ROAS) before launch109- Duration: 14-30 days recommended; minimum 2 weeks for bidding tests110111### LinkedIn A/B Testing112- Built into Campaign Manager for Sponsored Content113- Duplicate ad set with single variable change114- Target: same audience segment with automatic rotation115- Minimum budget: $50/day per variant116- Key metrics: CTR (>0.44% benchmark), CPL, Lead Form CVR (13% benchmark)117- Duration: 14-21 days (LinkedIn's smaller daily volumes require longer tests)118119### TikTok Split Testing120- Available in TikTok Ads Manager > Create A/B Test121- Test types: targeting, bidding, creative122- Auto-splits audience to avoid contamination123- Minimum 7 days, recommended 14 days124- Budget: minimum $20/day per ad group125- Creative tests: isolate hook (first 2-3 seconds) as the primary variable126- TikTok's enhanced split testing supports modular test variables (targeting, creative, budget, placement) via Smart+ since 2025127128## What to Test (Priority Order)129130### High Impact (test first)1311. **Creative concept** (different messaging angles, not just color changes)1322. **Hook/first 3 seconds** (video opening on Meta, TikTok, YouTube)1333. **Offer structure** (pricing, discount type, free trial length)1344. **Landing page** (headline, CTA, form length)1355. **Bidding strategy** (tCPA vs tROAS vs Maximize Conversions)136137### Medium Impact1386. **Audience targeting** (interest vs lookalike vs broad)1397. **Ad format** (static vs video vs carousel)1408. **CTA button** (Learn More vs Sign Up vs Shop Now)1419. **Campaign structure** (CBO vs ABO, consolidated vs segmented)142143### Low Impact (test last)14410. **Ad scheduling** (time of day, day of week)14511. **Device targeting** (mobile vs desktop)14612. **Minor copy variations** (word substitutions without concept change)147148## Common Testing Mistakes to Avoid149150- Testing too many variables at once (no clear winner attribution)151- Ending tests too early (before statistical significance)152- Testing during atypical periods (holidays, launches, incidents)153- Comparing unequal time periods154- Not documenting learnings (build institutional knowledge)155- Testing small changes when big changes are needed (optimize vs innovate)156- Ignoring learning phase on automated platforms157158## Output Format159160```161## A/B Test Plan162163### Hypothesis164IF [change]165THEN [metric] will [direction] by [amount]166BECAUSE [reasoning]167168### Test Design169| Parameter | Value |170|-----------|-------|171| Platform | [platform] |172| Test Type | [A/B / Multivariate] |173| Variable | [what's being changed] |174| Control | [current state] |175| Variant | [proposed change] |176| Primary Metric | [KPI] |177| Traffic Split | [50/50 / other] |178179### Sample Size & Duration180| Metric | Value |181|--------|-------|182| Baseline CVR | [X%] |183| MDE | [X%] |184| Required Sample | [N per variant] |185| Daily Traffic | [N clicks/day] |186| Est. Duration | [X days] |187| Min Duration | 7 days |188189### Success Criteria190- Winner declared at 95% confidence191- [Primary metric] improvement of [X%]+ sustained over [Y] days192- No negative impact on [secondary metric]193194### Setup Instructions195[Platform-specific step-by-step]196```