Insight

Sticky Add to Cart Limited Quick Decisions

Little Bible Stories already used a sticky add-to-cart element on its product pages, but the experience made quick purchase decisions harder than necessary. On desktop, colour selection sat inside a text dropdown instead of showing the same visual swatches used higher on the page, and the sticky element did not make the product price prominent. On mobile, the existing treatment only became useful after shoppers moved through the product content, despite returning or high-intent visitors potentially being ready to buy sooner. Blend’s CRO audit and competitor review identified an opportunity to make the purchase action easier to understand and reach. The recommendation followed our evidence-led CRO audit approach: turn observed interface friction into a controlled experiment and measure whether clearer options and more accessible placement improved the buying journey.

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A/B/C Test

Sticky Add-to-Cart Placement and Colour Swatches

We ran an A/B/C test on product pages. The control kept the original sticky add-to-cart. Both variants replaced the desktop text dropdown with visible colour swatches. Variant 1 positioned the mobile sticky CTA at the top of the viewport, while Variant 2 placed it at the bottom. We hypothesised that clearer variant selection and an easier-to-reach CTA would increase sticky-element clicks, add-to-cart rate and conversion rate, with conversion as the primary goal.

Variant 2 kept the improved desktop swatches but used a bottom-positioned mobile sticky CTA. This placement was easier to reach one-handed and allowed the test to isolate how mobile position affected purchase behaviour.

The Results

Variant 2 produced the strongest overall commercial trend. Compared with the control, sticky add-to-cart clicks increased 27%, add-to-cart rate rose 8% and conversion rate improved 7%, while revenue per visitor remained level. The mobile segment supported the accessibility hypothesis: Variant 2 increased sticky clicks 12%, add-to-cart rate 9% and conversion rate 8%. Its bottom placement was likely easier to reach with one hand. The trade-off was an 18% decrease in mobile revenue per visitor, while desktop conversion fell 5% even though desktop sticky clicks increased 148% and revenue per visitor rose 3%. Device-level results had not reached statistical significance, so these splits should be treated as directional. Variant 1 was less consistent overall, despite stronger desktop conversion and revenue per visitor. Blend recommended Variant 2 because it delivered the best overall balance across engagement and conversion measures. The client approved the rollout, and the variant was made live. A follow-up test should examine the mobile revenue-per-visitor decline and whether CTA timing, product mix or order value explains it.

  • 27%

    increase in sticky add-to-cart clicks

  • 8%

    increase in add-to-cart rate

  • 7%

    increase in conversion rate
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