# Sticky add-to-cart bar: +45.3% desktop add-to-cart, sales fell

- 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/tactical-bottom-sticky-add-to-cart/
- Page: https://liftarchive.com/test/cleancommit-tactical-bottom-sticky-add-to-cart/

Adding a sticky add-to-cart bar to product pages raised desktop add-to-cart rate by 45.3%, but overall conversion rate fell 10.6%. Clean Commit ran this test for an anonymized Shopify store and published it in its A/B test library. The agency labelled the outcome inconclusive, and we treat it the same way.

## Result

**+45.3% desktop add-to-cart, sales fell**

- Add-to-cart rate on desktop rose 45.3%: far more shoppers put items in the cart.
- Click-through rate across all devices rose 3.3%, a small lift in engagement.
- Bounce rate on desktop fell 30.2%, so fewer visitors left straight away.
- Conversion rate across all devices fell 10.6%. This is the number that matters most, and it went the wrong way.
- Overall: inconclusive. More carts did not turn into more orders.

## Control

The product page had no sticky add-to-cart bar. Shoppers had to scroll back up to the main button to add an item.

## Variant

A sticky add-to-cart bar stayed on screen as shoppers scrolled. The agency's hypothesis also mentions a size selector with a preselected size inside the bar.

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

- A bar that is always in view makes adding to cart easy, so it pulls in low-intent clicks from shoppers who were not ready to buy.
- If a size is preselected, some shoppers may add the wrong size, then drop out in the cart once they notice.
- The gap between add-to-cart and orders points to friction later in the funnel, which a product page change cannot fix.
- With no sample size or probability shared, part of the swing may simply be noise.

## Caveats

No sample size, duration or significance figures were shared. The page title says bottom bar while the hypothesis describes a top bar, so the exact placement is unclear.

## How to run this test

- Hypothesis: If we add a sticky add-to-cart bar to product pages, then more shoppers will complete an order because the button stays within reach as they scroll.
- Primary metric: Conversion rate (orders per visitor), not add-to-cart rate
- Guardrail: Cart abandonment rate
- Guardrail: Revenue per visitor
- Guardrail: Return or exchange rate if a size is preselected
- Who should test it: Stores with long product pages where the main button scrolls far out of view. Be careful with sized products: do not preselect a size, and judge the test on orders, not carts.

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Credit: Clean Commit ran this test and owns the result. Summary and commentary by LiftArchive (https://liftarchive.com/test/cleancommit-tactical-bottom-sticky-add-to-cart/).
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.