PerTronix
Adding a Sticky Add to Cart on Desktop
Hypothesis
What the Data Told Us
We conducted user testing for PerTronix and during this analysis, we found that users experienced the “Add to Cart” button disappearing while scrolling through the page. This created an action proximity gap, where purchase intent could form while the primary conversion mechanism was no longer within immediate reach. The audience for this client is always interested in specs, installation guides, etc., before making their purchase, causing them to scroll far down on the product detail page before making a decision. We hypothesised that introducing a sticky Add to Cart bar on desktop would keep essential product details and purchase options visible. For research-led products, requiring users to retrace their steps to complete an action can introduce unnecessary friction and interrupt decision momentum at the point of readiness.
A/B Test
What We Did
We ran an A/B test where the Original didn’t have a sticky Add to Cart versus a variant featuring a persistent sticky Add to Cart bar. This ensured purchase capability remained continuously available without disrupting the informational depth that users relied on during evaluation.
The Results
The sticky Add to Cart bar delivered strong uplifts across both engagement and revenue metrics, indicating that users were able to read through all the required information and add products to their carts immediately without having to scroll back to the Add to Cart CTA. Conversion Rate increased by +25.95%, while Revenue per Visitor rose by +25% and Total Revenue by +29.9%. The improvement suggested that maintaining persistent action visibility preserved conversion momentum, enabling users to act immediately once information needs were satisfied.
User behaviour also improved meaningfully, with clicks on Add to Cart increasing by +14.76%, Average Products per Visitor by +18.69%, and Average Order Value rose by +6.3%. These results reinforced that reducing action retrieval effort, particularly within research-heavy journeys, can materially improve conversion outcomes by aligning purchase availability with moments of decision readiness.
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25.95%
Increase in Conversion Rate -
29.9%
Increase in Total Revenue -
18.69%
Increase in Average Products per Visitor
2025
WINNER
Standout CRO Agency of the Year
2025
WINNER
eCommerce Agency of the Year (Small)
2025
WINNER
UK eCommerce Medium Agency of the Year
2025
WINNER
CRO Agency of the Year
2022
WINNER
CRO Agency of the Year
2022
WINNER
CRO Agency of the Year
2022
WINNER
Dev Agency of the Year – Medium
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