# A/B tests

> Test versions of a rule against each other, pick the goal that decides the winner, and read whether the difference is real.

An A/B test shows different versions of one rule to different visitors, so you can see which works better. To measure what all your rules add together, use a [holdout](https://geoengage.app/docs/rules/holdouts) instead.

## A/B testing a rule

In the rule editor, turn on **A/B Testing** under Advanced Settings.

**One version against nothing.** Name your variant and set its **Traffic Split**. That share of the rule's visitors see its action; the rest are the *control* and see nothing, which is the fairest test of whether the action helps at all.

**Several versions.** Add variants to the **Variants** list, each with its own share of traffic (the shares must add up to 100). A variant can have its own action — different copy, a different offer, a different kind of action altogether — or fall back to the rule's. A variant named `control` always shows nothing.

**Success Goal.** Pick the [goal](https://geoengage.app/docs/analytics/goals) the test is judged on, such as a purchase or a signup. Without one, the test only counts impressions.

Each visitor is assigned a variant once and keeps it on later visits, so no one sees the rule change from page to page.

## Reading the result

Open **Rules & A/B Tests** in the dashboard. For each variant it shows how many visits saw it and how many completed the goal, and whether the difference is real:

- It waits for at least 100 visits in each variant. Before that, it says there aren't enough visits yet to tell them apart.
- It calls a difference only when it's statistically significant, at the 5% level. A variant that is significantly *worse* is reported as well: losing is a result too.

> [!TIP]
> Decide how long the test will run before you start, and don't stop it the first time it looks like it's winning. Early leads come and go; that's what the 100-visit floor guards against.

## Testing more than one rule

Each A/B test judges one rule. To find out whether personalization works across the whole site, compared with visitors who get no rules at all, run a [holdout](https://geoengage.app/docs/rules/holdouts).

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Source: https://geoengage.app/docs/rules/ab-tests