One size filter above the fold: +2% revenue per visitor
Test run byOptimizelyTesting and CRO tool
Commentary byLiftArchiveOur analysis, not theirsMerging men's and women's shoe size filters into one option and moving it above the fold raised revenue per visitor by 2%.
Optimizely ran the test for a footwear retailer and published it as an Optimizely Field Notes use case.
The vendor puts the value at about $12.7M in incremental revenue.
- Revenue per visitor: +2%. This is the headline number.
- Size filter use: +33.8%, which shows shoppers wanted to filter by size.
- Incremental revenue: about $12.7M, as estimated by Optimizely. The source page does not say what time period this covers.
- Sample size, test length and confidence level were not shared.
The change
Two size filters became one and moved above the fold.
Simplified mockup drawn by LiftArchive from the shared screenshots.
Control
Men's and women's sizes sat in separate filters, placed where shoppers were less likely to see them.
Variant
Both size ranges were combined into a single size filter shown above the fold.
Why it likely won
Our reading of the result, not the practitioner's claim.
- Shoppers often care first about whether a shoe comes in their size, so a visible size filter matches how they shop.
- Filtering early saves shoppers from opening a product only to find their size is out of stock.
- One combined filter is simpler than two, especially for unisex styles or shoppers buying for someone else.
Caveats: Anonymized vendor summary with no sample size, duration or confidence level. The $12.7M figure is the vendor's own estimate, and its time period is not stated.
Who ran it
Optimizely ran this test for a footwear retailer (Optimizely customer) and published the results (Optimizely Field Notes use case). The numbers are theirs; the summary and commentary on this page are ours.
Read the original case study on Optimizely →
How to run this test on your store
- Hypothesis
- If we merge size filters into one option and show it above the fold, then revenue per visitor will rise because shoppers only see products available in their size.
- Primary metric
- Revenue per visitor
- Guardrails
- Size filter usage
- Zero-result filter rate
- Product page exits after size selection
- Who should test it
- Footwear and apparel stores where size availability varies a lot by product. Less useful for one-size products or small catalogs where shoppers can scan everything anyway.
Questions
Where should size filters go on a shoe store?
In this test, moving a single size filter above the fold raised revenue per visitor 2%.
Size is often the first thing shoe shoppers filter by, so make it easy to find.
Should men's and women's sizes be separate filters?
This retailer did better with one combined filter.
Test it if you sell unisex styles or see shoppers browsing both ranges.
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