# Setting up a Cross-Site A/B Test

Run a true end-to-end A/B test by comparing entire Shopify themes and their connected checkout experiences

May 7, 2026

A Cross-Site A/B Test compares the performance of **different Shopify themes** against each other. Traffic is split between your themes, and PDQ tracks how each performs against your goal metric. It's the right call when you're testing a redesigned theme against your current live one before fully committing.

For the why-and-when explainer, see [Introducing: Cross-Site Testing](https://support.prettydamnquick.com/en/articles/13509803-introducing-cross-site-testing).

# Step 1: Create the test

In the left sidebar, go to **Optimize > A/B Tests**. Click **New Test** and select **Cross-Site Test** from the dropdown.

# Step 2: Fill in the details

- **Test Name** — short and clear (e.g. "New Theme Redesign vs Current Live Theme").  
- **Hypothesis** — what you expect to learn (min. 100 characters). Be specific: "The new theme redesign will improve checkout conversion by providing a cleaner, more streamlined experience for our customers."  
- **Goal Metric** — Checkout Conversion, Gross Profit, AOV, Shipping Revenue, or Net Revenue.

Click **Next**.

# Step 3: Allocate traffic

You'll see your available Shopify themes. For each theme you want to include:

- Set the **traffic percentage** directed to it.
- Assign a **Checkout Group** — this determines which PDQ extension setup is served alongside that theme.

Percentages across all included themes must add up to 100%.

_Make sure the checkout group assigned to each theme matches the experience you want to serve. This controls the full checkout that shoppers in that group will see._

# Step 4: Install the PDQ script

For PDQ to route traffic correctly, you need to install a small script in each theme being tested. In the test, go to the **Installation** tab and follow these steps for every theme:

1. Copy the provided script snippet.  
2. In Shopify, go to **Online Store > Themes**.  
3. Click **...** next to the theme and select **Edit code**.  
4. Open the **theme.liquid** file.  
5. Paste the script just before the closing **</head>** tag and save.

Repeat for every theme included in the test.

# Step 5: Launch the test

Once traffic allocation is set and the script is installed in all themes, go back to PDQ. Find your test in the **Drafts** tab, click **⋯**, and select **Start Test** to go live.

# Managing your test

- **Editing a draft** — Find it in the **Drafts** tab, click **⋯**, select **Edit**.
- **Launching** — Click **⋯** on the draft, select **Start Test**. Goes live immediately.
- **Monitoring** — A **Running** tab appears between Drafts and Concluded once at least one test is active. Performance data lives in **Optimize > Analytics Dashboard**, available the day after launch.
- **Ending** — In the Running tab, click **⋯**, select **End Test**. View final results in **Optimize > Analytics Dashboard**, or click **⋯** in Concluded and pick **Get Analytics**.

Happy testing! Reach out to [support@prettydamnquick.com](mailto:support@prettydamnquick.com) if you need help.