BAYESIAN

Bayesian A/B Testing

Make confident decisions with probabilities instead of p-values, understanding exactly how likely each variant is to be the winner

What We Do

Posterior-focused analysis and decision metrics.

Estimate Posteriors

Compute posterior for each variant (Beta updates for binary outcomes) with credible intervals.

Simulate Outcomes

Draw posterior samples to estimate P(best), pairwise probabilities, and expected loss.

Analyze Uplift

Summarize absolute/relative uplift vs control with credible intervals.

Recommend Actions

Provide decision metrics: recommendation, confidence, expected risk, sample size status.

What You’ll Receive

Direct mapping to the analysis module’s result object.

Decision Metrics

Best performing variant with probability of being best, expected loss if wrong, sample sizes analyzed, confidence levels, and clear go/no-go recommendations

Statistical Analysis

Conversion rates with credible intervals, probability each variant is best, head-to-head comparisons, uplift vs control with confidence bands, decision recommendations

Visualization Data

Posterior probability distributions, credible interval plots, Monte Carlo simulation results, uplift charts showing relative and absolute improvements

What Makes This Powerful

Posterior Uplift

Posterior distributions, credible intervals, and P(B > A) for uplift decisions.

Expected Loss

Decision rules based on expected loss/utility, with ROPE thresholds for practicality.

Sequential Friendly

Optional sequential monitoring without p‑hacking; stop early when confident.

What You Need to Provide

Required Data Structure

Your data needs a group_column (variant names like A/B or control/treatment) and outcome_column (binary 0/1 for conversion). Each row represents one user/session.

Data format: Simple table with variant labels and conversion outcomes. Supports multiple treatment variants vs control. Binary outcomes only (converted/not converted).

Minimum requirements: At least 100 conversions per variant recommended, ideally 1000+ samples per variant for reliable posterior distributions.

What you get: Probability that each variant is best, expected loss if you choose wrong, credible intervals showing uncertainty, and clear recommendations based on your risk tolerance.

Schema Preview / variant, id, metric[, covariates]

Quick Specs

Metricsbinary, rate, or continuous
Priorsweakly informative (configurable)
OutputsP(B>A), CI, expected loss
Monitoringsequential optional

How We Decide with Bayes

From priors to decision thresholds

1

Specify & Prepare

Define metrics and priors; clean data, check randomization, and stratify if needed.

2

Update Posteriors

Compute posterior distributions; summarize uplift, credible intervals, and P(best).

3

Decide & Monitor

Apply expected‑loss rules and ROPE; optional sequential monitoring for early stopping.

Why This Analysis Matters

Bayesian testing offers direct, intuitive probabilities and allows principled monitoring—speeding decisions while reducing false stops.

Move from “is it statistically significant?” to “how likely is this better, by how much, and what’s the downside risk?”. Stakeholders get credible intervals and expected loss for confident go/no‑go calls.

Note: Good randomization and metric definitions are critical. For complex heterogeneity or many variants, consider hierarchical models or adaptive designs.

Ready to Test Smarter?

Make probability‑based decisions with clear risk tradeoffs

Read the article: Bayesian A/B Testing