Blog

Donnu A/B Blog

Complete, honest guides on CRO, A/B testing and experimentation. The most complete articles on the web, no fluff. (page 5 of 17)

Statistics

Novelty Effect in A/B Testing: How to Detect It

What the novelty effect is, how to tell a real decaying effect from a statistical artifact, and the three checks that separate a fad from a durable win.

Statistics

Sample Ratio Mismatch (SRM) in A/B Testing

What sample ratio mismatch is, how the chi-square check works, how small an imbalance already invalidates a test, and how to find the root cause.

Tools

GrowthBook vs PostHog: Which Open-Source Tool to Choose

GrowthBook vs PostHog compared by criterion: statistics engine, self-hosting weight, SDK role, data source, and which team profile each one actually fits.

A/B Testing

How Many Visitors Do You Need for an A/B Test?

How many visitors an A/B test needs, with a full reference table by baseline rate and effect size, the arithmetic behind it, and what to do on low traffic.

Statistics

Minimum Detectable Effect: How to Choose the MDE

What minimum detectable effect means, how to pick an MDE you can defend, absolute versus relative, and what your traffic can actually resolve.

A/B Testing

A/B vs Multivariate vs Split URL Testing: Which to Use

A/B vs multivariate testing in practice: a comparison table, the interaction effect, the real sample cost per cell and a decision tree with a calculator.

Tools

AI Copilots in A/B Testing Tools: What They Actually Do

What AI copilots in A/B testing tools really do, what they cannot do by construction, and a script to evaluate one without outsourcing the decision.

CRO

Personalization vs A/B Testing: When to Use Which

Personalization vs A/B testing: the different questions each one answers, the real traffic cost of segmenting and a decision rule with a calculator.

A/B Testing

AI-Generated A/B Test Variations: Do They Work?

AI-generated A/B test variations: what the evidence shows, the statistical cost of testing many at once and how to use them without breaking rigor.