# A/B test with and without an OptiMonk campaign Canonical URL: https://support.optimonk.com/en/articles/a-b-test-with-and-without-an-optimonk-campaign How much extra revenue does your popup actually bring in? The only honest way to answer that is to keep a slice of your traffic away from the campaign and compare. That slice is called a **control** — a holdout bucket that sees nothing. In OptiMonk you don't have to fake it with code. The campaign's A/B test has a built-in control arm: - **Your design** — visitors who see the popup. - **Control (no popup)** — visitors who see nothing at all. Traffic is split between the two, and the campaign's Overview tab shows the uplift and the chance to win for each arm. You don't need Google Analytics for the comparison — though you can still cross-check there if you want to. --- ## Add the control arm 1. Open **Campaigns** in the left menu and click the campaign you want to measure. 2. Stay on the **Overview** tab. Under the metrics band you see the variants table with the columns **Traffic · Variants · Active · Impressions · Submits · Submit rate · Uplift**. 3. Click **+ Add A/B test variant** under the table. 4. Choose the first option, **Control (no popup)** — *A holdout bucket that sees nothing*. While it is being created you see *Adding control variant…* and *This can take a few seconds — it's syncing with OptiMonk.* 5. The control appears as a new row in the table. It has no preview image — instead of a thumbnail it says **No variant will be shown**, which is exactly what it does. You can only add **one** control per campaign. If one is already there, the menu item is greyed out and says *Already added*. **Make sure both rows are switched on.** The **Active** toggle in each row decides whether that arm takes traffic. A control that is switched off is not measuring anything. --- ## How the traffic is split Traffic is shared **equally** across all active variants: with one design and one control, half your visitors see the popup and half see nothing. Click the percentage in the **Traffic** column to open **A/B test settings**. There, under **Traffic share**, you see each active variant with its share and the total. The **Evenly split** checkbox is marked **Always on**: *Traffic is shared equally across all active variants.* A custom split is not available yet — if you click the checkbox, the panel tells you: *Custom traffic split is still in progress. For now, traffic is always distributed evenly across active variants.* --- ## Read the result Once both arms have traffic, the campaign's **Overview** tab answers the question directly. **The banner at the top of the table** says **A/B test running** and names the leader: *Design A ****is leading by**** +14.20% (73% chance to win) * Before there is enough data it says *Data collection in progress.* instead. **The metrics band above it** shows **Conversion uplift** as its headline number, with *{pct}% chance to win* underneath. If there aren't enough conversions yet it says *Not enough conversions yet to calculate uplift.* **In the variants table**, each row has its own **Uplift** column. The control is the baseline, so its uplift cell shows a dash — every other row is measured against it. Rows also show *{pct}% to win*. A **+18%** uplift against a *Control (no popup)* arm reads literally: visitors who saw the popup converted 18% more often than the ones who didn't. That is the incremental effect of the campaign, with no attribution modelling in between. --- ## End the test You can let OptiMonk end it for you, or call it yourself. **Automatically.** In **A/B test settings**, **Auto-declare winner** is on by default: *Automatically end the test when a clear winner emerges.* The defaults are **Declare at 95% chance to win**, **Min conversions 200** and **Min days running 3** — all three have to be met. Change any of them in the same panel. **By hand.** Click **Declare winner at 95%** in the green banner. If the leader hasn't reached your threshold, OptiMonk asks first: **Declare winner now?** *"Design A" is leading with a 71% chance to win — below your 95% threshold. Ending the test now may pick a winner that isn't statistically reliable yet. ***Keep testing** / **Declare anyway ** If there is not enough data to tell the arms apart at all, it says so instead: *There isn't enough data yet to tell the variants apart. Ending the test now keeps "…" active and stops the others based on little or no evidence.* When the control wins, that is a real answer too — it means this particular campaign is not paying for itself in its current form. Change the offer or the design and test again. --- ## Remove the control Open the **⋮** menu at the end of the control's row and choose **Delete**. The campaign keeps running with the remaining variants. You can add the control back later from the same **+ Add A/B test variant** menu.