# Mobile sticky add-to-cart: +6.8% adds, -7.7% conversion rate

- Outcome: Flat / inconclusive
- Page type: Product page (Ecommerce)
- Elements: Sticky add-to-cart bars
- Test run by: [Clean Commit](https://liftarchive.com/practitioners/clean-commit/)
- Commentary by: LiftArchive (our analysis, not theirs)
- Original source: https://cleancommit.io/ab-tests/mobile-bottom-sticky-add-to-cart-button/
- Page: https://liftarchive.com/test/cc-mobile-bottom-sticky-add-to-cart-button/

Pinning the add-to-cart button to the bottom of the mobile screen raised add-to-cart rate by 6.8% but lowered conversion rate by 7.7%, an inconclusive result. Clean Commit ran this test for an anonymized Shopify store and published it in its A/B test library. On the target metric, the variant had only a 50.6% probability of beating the original.

## Result

**+6.8% adds, -7.7% conversion rate**

- Add-to-cart rate: +6.8%, the target metric, but only a 50.6% probability of beating the original. Inconclusive.
- Conversion rate: -7.7%, a negative but not significant result.
- Revenue per visitor: -22.1%, as average order value fell 15.5%.
- Orders: -6.1%.

## Control

On mobile, the add-to-cart button sat in its fixed section of the product page.

## Variant

The add-to-cart button stayed fixed at the bottom of the mobile screen as shoppers scrolled.

## Why it likely came out this way (our reading)

- An always-visible button makes adding easy, but does not answer the questions that lead to buying.
- Easier adds may bring in shoppers who were less sure, who then drop off before checkout.
- The order value drop may be noise in a small sample rather than an effect of the button.

## Caveats

7,948 mobile visitors over 15 days, and no metric reached significance. Metrics moved in opposite directions.

## How to run this test

- Hypothesis: If we make the add-to-cart button sticky at the bottom of mobile product pages, then add-to-cart rate will rise because shoppers don't have to scroll back to find it.
- Primary metric: Add-to-cart rate on mobile
- Guardrail: Conversion rate
- Guardrail: Revenue per visitor
- Guardrail: Average order value
- Who should test it: Stores with long mobile product pages where the buy button scrolls out of view. If your page is short, a sticky button adds little. Judge it on orders, not just adds.

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Credit: Clean Commit ran this test and owns the result. Summary and commentary by LiftArchive (https://liftarchive.com/test/cc-mobile-bottom-sticky-add-to-cart-button/).
Usage: Free to use, quote and build on, with credit and a link: name the practitioner or organization that ran the test and link to its LiftArchive page. The results belong to the practitioners who ran and shared them; the summaries and commentary are LiftArchive's.