Hypothesis

What We Wanted to Learn

Each month, as part of our ongoing CRO Implementation program, our strategists spend time analysing each client site. During this analysis, we observed that users had to scroll to reach the purchase CTA on the PDP, adding friction at a critical decision point. We hypothesised that keeping a purchase CTA visible while browsing would reduce effort, speed up decision-making, and increase add-to-cart actions. To test the impact of different CTA formats, we introduced two sticky variations on the PDP.
Jump to results

Variant 1: Sticky Add to Cart

Keeping One-Time Purchase CTA Visible

Variant 1 introduced a persistent Sticky Add to Cart CTA that remained visible while scrolling. The goal was to provide a clear, low-commitment action at all times, making it easier for shoppers to add the product to their basket when they were ready, without needing to scroll back up or down the page.

Variant 2: Sticky Subscribe & Save

Highlighting Subscription Benefit

Variant 2 used the same persistent placement, but promoted a 10% Subscribe & Save option. This tested whether buyers would be more likely to convert if the subscription incentive was more visible while browsing. The intention was to increase recurring purchases and average product value by nudging subscription behaviour.

The Results

Both sticky CTAs drove meaningful improvements across conversion and revenue. However, the Sticky Add to Cart CTA (Variant 1) consistently outperformed the Subscribe & Save CTA (Variant 2) across most metrics.

Variant 1 increased Conversion Rate increased by +47.61%, Revenue per Visitor by +48.28%, and Average Products per Visitor by +47.10%. Engagement and checkout visits also rose, while bounce rate slightly declined (-0.41%).

Variant 2 delivered solid gains, with Conversion Rate up +28.56% and Revenue per Visitor up +31.36%. However, results were weaker than Variant 1, likely because subscriptions add extra decision-making and aren’t as broadly appealing as one-time purchases.

Based on these findings, we implemented Variant 1 as the default sticky CTA on PDPs, as it produced the strongest impact on both conversion and revenue.

  • 47.61%

    Increase in Conversion Rate

  • 48.28%

    Increase in Revenue per Visitor

  • 47.10%

    Increase in Average Products per Visitor
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