All tests
CVRProduct pageApparel
Sticky ATC on mobile PDP
Visible CTA on scroll removes friction for mobile shoppers making a buying decision.
Winner
+11.3%
Add-to-cart rate
18,432
Sessions
97%
Confidence
14d
Duration
Variant A — Control
No sticky add-to-cart — button only above the fold.
Variant B — Treatment
Sticky add-to-cart appears on mobile when the main CTA scrolls out of view.
What we took away
B — Variant won
Worked best on PDPs with long scroll (reviews + extensive spec sections). Minimal lift on short PDPs — bar disappeared off-screen before users scrolled.
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