> ## Documentation Index
> Fetch the complete documentation index at: https://docs.abconvert.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Statistical Significance in A/B Testing Explained

> Learn how to read statistical significance in Analytics v2, including p-values, confidence intervals, and Bayesian win probabilities.

This page helps you answer one practical question: "How strong is the evidence for this result?"

Before you read the statistics, choose the metric that best matches the Test goal. See [How to interpret Analytics results](/analytics/interpret-results) for the full decision workflow.

Analytics v2 gives you two statistical views of the same Test:

* **Frequentist analysis** for clear pass/fail decision support.
* **Bayesian analysis** for early directional guidance when traffic is still low.

Use both together when you review the selected metric.

## Key facts

* A p-value shows the strength of evidence that the observed difference is unlikely to be random noise.
* A confidence interval shows uncertainty around the estimated impact.
* Prob. Beat Control and Prob. Be Best estimate how likely a variant is to beat control or be best for the selected metric.
* More visitors, conversions or orders, and run time make results more stable.

## Frequentist analysis: clear decision support

Frequentist analysis is useful when you need structured evidence for go or no-go decisions.
In Analytics v2, this view is represented mainly by **p-value** and **confidence interval**.

### How to read p-value

A p-value describes how surprising the observed result would be if there were no real difference between variants.

Lower p-values are stronger evidence that the observed difference is unlikely to be random noise under the test assumptions.

| P-value     | What it means                                                                                |
| ----------- | -------------------------------------------------------------------------------------------- |
| > 0.10      | Weak evidence. Usually too early or no clear difference.                                     |
| 0.05 - 0.10 | Borderline. Keep running the Test.                                                           |
| \< 0.05     | Statistically significant. Strong evidence against no difference under the test assumptions. |
| \< 0.01     | Very strong evidence.                                                                        |

<Note>
  A p-value below 0.05 does not mean there is a 95% chance your variant is
  better. It means the observed gap is unlikely to be random noise.
</Note>

### How to read confidence intervals

Confidence intervals show a likely range for the true impact, based on the data and method.

A narrow range means a more stable estimate. A wide range means more uncertainty. A range that includes both good and bad outcomes means the result is still mixed.

For example, if Revenue per Visitor is 2.40 and the interval is \[1.10, 3.70], the true value could reasonably fall anywhere in that range.

<Frame caption="Review confidence intervals and uplift values in the statistical significance table">
  <img src="https://mintcdn.com/abconvert/VFmi9qAFbJQj1ajO/images/analytics/statistical-significance-frequentist-results.png?fit=max&auto=format&n=VFmi9qAFbJQj1ajO&q=85&s=500ab23640d2ffdc623eeb22641896be" alt="Statistical significance table comparing Control and Variant A with uplift percentages and value ranges for each group" width="2290" height="894" data-path="images/analytics/statistical-significance-frequentist-results.png" />
</Frame>

## Bayesian analysis: early directional guidance

Bayesian analysis is useful when you do not have enough traffic for a strong frequentist result yet.
It helps you understand which variant is leading right now and how stable that lead looks.

* **Prob. Beat Control**: the model-estimated chance that a variant is better than control for the selected metric.
* **Prob. Be Best**: the model-estimated chance that a variant is best among all variants in the Test.

These probabilities can change as more data arrives. Read them for the selected metric and model shown in the dashboard.

<Frame caption="Track how a variant's win chance changes over time for the selected metric">
  <img src="https://mintcdn.com/abconvert/VFmi9qAFbJQj1ajO/images/analytics/statistical-significance-bayesian-win-chance.png?fit=max&auto=format&n=VFmi9qAFbJQj1ajO&q=85&s=63d8170ffbf73b29c6d1c9a9db7561ee" alt="Performance overview chart on the Win chance tab showing Variant A probability trend for Conversion Rate over several dates" width="2276" height="1252" data-path="images/analytics/statistical-significance-bayesian-win-chance.png" />
</Frame>

<Tip>
  Do not decide based on one snapshot. Look for a consistent pattern across
  multiple refreshes.
</Tip>

## How to use frequentist and Bayesian results together

ABConvert shows both statistical systems. Read them in this order:

<Steps>
  <Step title="Start with Bayesian direction">
    Check **Prob. Beat Control** and **Prob. Be Best**. If they are unstable or
    keep flipping, keep running the Test.
  </Step>

  <Step title="Confirm with frequentist evidence">
    Before final rollout, verify that p-value is below 0.05 and confidence
    intervals are not too wide.
  </Step>

  <Step title="Check business sanity">
    Make sure uplift is meaningful for your store, not just statistically
    detectable.
  </Step>

  <Step title="Decide and ship">
    Launch the winning variant when Bayesian trend and frequentist evidence both
    support the same direction.
  </Step>
</Steps>

<Info>
  Run your Test for at least one full business cycle before making a final
  decision. For most stores, that means around 1-2 weeks so weekday and weekend
  behavior are both included. You still need enough visitors, conversions or
  orders, and balanced traffic.
</Info>

## What to do when results are inconclusive

Sometimes the result is still unclear after several days. That is normal.
If the statistical result is still mixed, do this:

* Keep the current winner (usually control) while you collect more data.
* Extend the run window and review again after more traffic arrives.
* Check segments such as country, device type, or visitor type to find hidden differences.
* If signals stay flat, treat it as "no meaningful difference" and test a bigger idea next.

Inconclusive results are still useful. They tell you your current variant is not strong enough to justify a rollout yet.
