Does a sticky add to cart bar lift product page sales?
The add to cart button scrolled out of view as shoppers read down the product page. We tested a sticky add to cart bar that appeared once that button left the screen. On mobile, conversion rate moved 0.6% over 18 days, too small to call.
Not significant Mobile 18 days Not called
The hypothesis
By showing a sticky add to cart bar once the main button scrolls away, we will keep the next step in view, resulting in more shoppers adding to cart and buying.
Product pages on this store are long. Shoppers read details and reviews well below the main button, and to buy they have to scroll back up.
A sticky bar keeps the action in reach wherever the shopper is on the page. On desktop we also tried a version that added the product name and star rating to the bar, to give it more context.
What we changed
We added an add to cart bar that sticks once the main button scrolls off.
In the control, the add to cart button sat near the top of the page and disappeared as shoppers scrolled. Variation A added a simple add to cart bar that appeared once the main button left the screen. Variation B, on desktop only, added the product name and star rating to the bar. Mobile ran Variation A only, because product names were too long to fit.
- Add to cart bar appears once main button scrolls off
- Bar stays fixed while the shopper scrolls
- Same sticky add to cart bar
- Product name added to the bar
- Star rating added to the bar
- Desktop only
The result
Mobile conversion rate moved 0.6% with the sticky add to cart bar.
On mobile, Variation A moved conversion rate 0.6% and revenue per visitor 19.2% over 18 days. Early weeks looked positive, but the results leveled out as more traffic came in, and neither number reached our 90% confidence bar.
On desktop, Variation A showed a larger conversion lift of 33.5%, but desktop traffic was too low to tell a trend from noise. We paused Variation B partway through because it trailed on desktop.
What we would do next
The sticky bar did not change mobile buying enough to call.
On this page the main button was already easy to find, so keeping it in view added little on mobile. The desktop lift is worth a second look with more traffic before anyone acts on it. A retest could run desktop on its own, for longer, with the simple bar only.