ABtesting.tools

A/B testing guides

Practical guides to help you design better experiments β€” from picking the right test to deciding when to stop.

How to choose the right statistical test

Not sure whether to use a z-test, t-test, chi-square, or something else? Walk through a decision tree based on your metric type to find the right approach.

Read guide β†’

A/B test statistical significance explained

Learn what statistical significance really means, how p-values work, and why a 95% confidence level doesn't mean a 95% chance of being right.

Read guide β†’

Understanding A/B test sample size

Learn what determines sample size, how baseline rates and effect sizes interact, and the most common mistakes that lead to underpowered tests.

Read guide β†’

How long should you run an A/B test?

Convert sample size into calendar days, account for traffic volume and allocation, and understand why running tests in full-week cycles matters.

Read guide β†’

How to analyze A/B test results

Step-by-step guide to analyzing A/B test results correctly: check significance, effect size, confidence intervals, and make the right decision.

Read guide β†’

Bayesian vs frequentist A/B testing

Compare the two main statistical frameworks for A/B testing. Learn when to use each approach and how they interpret results differently.

Read guide β†’

Common A/B testing mistakes

Avoid the most common A/B testing mistakes: peeking at results, underpowered tests, wrong metrics, and more.

Read guide β†’

A/B testing for small traffic sites

How to run meaningful A/B tests with limited traffic. Strategies for small websites: bigger changes, Bayesian methods, and adjusted expectations.

Read guide β†’