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Category & Listing

How Many Products Per Page? A/B Test Example

Showing more products per page makes a wider selection available at once, but can increase page load.

  • Category listing
  • Product detail page visit rate

Option A vs Option B

How many are shown is the variable, not what they look like.

Changed
Quantity
Page
Category listing
Difference
changed

Hypothesis

The goal is to help visitors find products without harming performance; use product-detail visits as the primary outcome.

How to run this test

Primary metric

Product detail page visit rate

Compare eligible visitors who reach a product detail page after viewing the listing.

Other metrics

  • Purchase conversion rate (CR)Compare purchases among all eligible assigned visitors over the same follow-up window.
  • Page load timeMeasure listing load performance on the same devices and network conditions.
  • Listing exit rateCompare visitors who leave the listing experience.
  • Products actually seenCount products that entered the viewport; loaded products are not necessarily seen.

What to check before and during the test

  • Products per pageCompare 12 products per category page with 24.
  • Keep constantKeep product order, card design and loading behavior unchanged.
  • DiscoveryReview product clicks together with the number of products actually seen.
  • PerformanceTrack page load performance alongside discovery and purchase.
  • DeviceReview mobile and desktop separately.

Setup mistakes to avoid

  1. 1Change the number of products only; keep card design unchanged.
  2. 2Do not change lazy-loading or pagination behavior during the test.
  3. 3Do not interpret conversion in isolation if the listing becomes slower.
  4. 4Do not automatically apply a desktop result to mobile.
  5. 5Keep the product-ranking algorithm unchanged.