# Pick your size once, filter the whole site: +33% revenue

- Outcome: Won
- Page type: Site-wide (Ecommerce)
- Elements: Variant, size & option selectors, Filters, sorting & site search
- Test run by: [ConvertPolo](https://liftarchive.com/practitioners/convertpolo/)
- Commentary by: LiftArchive (our analysis, not theirs)
- Original source: https://wingify.com/success-stories/kisah-convertpolo-revenue/
- Page: https://liftarchive.com/test/kisah-persistent-preferred-size-selector/

Letting mobile shoppers choose their size once, early in the visit, and filtering the whole site to that size raised revenue by 33% and conversion rate by 28%. ConvertPolo ran this A/B test for Kisah, a men's ethnic wear brand, and it was published as a VWO case study.

## Result

**+33% revenue**

- Revenue: +33%. A large lift from one change to how size is handled.
- Conversion rate: +28%. More mobile visitors went on to buy.
- No sample size, duration or confidence level was shared, so treat the size of the lift with care.

## Control

Shoppers landed on the listing page and had to pick their size on each product page they opened.

## Variant

A preferred-size selector appeared early in the journey. The chosen size stayed in place across the site and filtered products to match.

## Why it likely won (our reading)

- Shoppers no longer repeat the same choice on every product, which saves taps on mobile.
- Filtering to the right size means shoppers only see items they can actually buy, so fewer dead ends.
- Clothing for special occasions is size-sensitive. Finding out late that an item isn't in stock in your size is a common reason to leave.

## Caveats

No sample size, duration or significance was given. A lift this large from one change is worth retesting on your own traffic.

## How to run this test

- Hypothesis: If we ask shoppers for their size once and filter products to it across the site, then more will buy because they skip repeat choices and only see items available in their size.
- Primary metric: Conversion rate
- Guardrail: Revenue per visitor
- Guardrail: Products viewed per session
- Guardrail: Return rate for wrong size
- Who should test it: Apparel and footwear stores where size matters and stock varies by size. It is less useful for one-size products, or where shoppers often buy for other people in different sizes.

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Credit: ConvertPolo ran this test and owns the result. Summary and commentary by LiftArchive (https://liftarchive.com/test/kisah-persistent-preferred-size-selector/).
Usage: Free to use, quote and build on, with credit and a link: name the practitioner or organization that ran the test and link to its LiftArchive page. The results belong to the practitioners who ran and shared them; the summaries and commentary are LiftArchive's.