What is A/B Testing?
A/B Testing is a method of comparing two versions of an ad, landing page, or creative element (Version A vs Version B) to determine which performs better based on a defined metric such as CTR, CVR, or cost per result.


Notch
Nov 13, 2025
Table of contents
What is A/B Testing?
A/B Testing is a method of comparing two versions of an ad, landing page, or creative element (Version A vs Version B) to determine which performs better based on a defined metric such as CTR, CVR, or cost per result.
It helps advertisers make data-driven decisions by isolating a single variable and measuring its real impact.
Why does A/B Testing matter right now?
Because algorithms optimize delivery, but creative and experience decisions still require human validation.
A/B testing ensures that the angles, hooks, layouts, and messaging you feed into AI systems are genuinely effective, improving performance and reducing wasted spend in a competitive, privacy-first ecosystem.
The Cognitive Ladder: Learning A/B Testing Step by Step
Stage 1: What is A/B Testing in Advertising?
A/B testing is a controlled experiment where two variations are compared to determine which performs better.
It isolates one variable at a time to measure its impact accurately.
Stage 2: What Does A/B Testing Do in a Campaign?
It helps you identify winning creatives, landing page elements, or messaging angles.
This leads to clearer optimization decisions and more predictable performance improvements.
Stage 3: Where Does A/B Testing Fit in the Marketing Workflow?
It fits in the creative optimization and experimentation phase.
Before scaling spend, A/B testing helps validate which version resonates most with your target audience.
Learn how LPO uses A/B testing at Landing Page Optimisation.
Stage 4: Why Does A/B Testing Matter for Performance?
Because every key metric CTR, CVR, CPA, ROAS improves when you identify the best-performing version.
A/B testing reduces uncertainty and ensures optimizations are based on real user behavior, not assumptions.
Stage 5: How Can You Master A/B Testing?
You master it by designing clean experiments with clear hypotheses.
Test one variable at a time (headline, image, CTA, layout)
Split audiences evenly and fairly
Let tests run long enough to gather reliable data
Define success metrics before the test begins
Mastery = clean variables + meaningful sample sizes + clear measurement.
Stage 6: What Mistakes Should You Avoid in A/B Testing?
Avoid testing too many things at once or stopping tests too early.
Overlapping audiences corrupt data
Changing multiple elements hides what caused the improvement
Ending tests prematurely creates false positives
Patience and structure are key.
Stage 7: How Do You Evolve A/B Testing Into an Advanced Skill?
You evolve it by using multivariate testing and AI-assisted experimentation.
Advanced advertisers use machine learning to predict which variants will likely win, auto-generate new creative versions, and continuously test in cycles linked to performance algorithms.
Explore automated creative iteration in Successor AI™ (/help/glossary/successor-ai).
Stage 8: What Should You Learn After A/B Testing?
Learn Split Testing next.
A/B testing compares two versions; Split Testing expands the concept to multiple variations and often across multiple audiences or placements.
Quick Learning Recap
Stage | Question | Key Takeaway |
1 | What is A/B testing? | A controlled experiment comparing two versions. |
2 | What does A/B testing do? | Identifies winning creatives or experiences. |
3 | Where does A/B testing fit? | In creative optimization and pre-scaling testing. |
4 | Why does it matter? | Reduces guesswork and boosts campaign performance. |
5 | How to master it? | Run clean, focused, hypothesis-driven experiments. |
6 | Mistakes to avoid? | Testing too many variables or ending tests early. |
7 | How to evolve it? | Use multivariate and AI-driven experimentation. |
8 | What next? | Learn Split Testing for multi-variant comparisons. |