# Heureka ratings slide-in on the left of product pages: +7.5% revenue

- Outcome: Won
- Page type: Product page (Ecommerce)
- Elements: Reviews & star ratings, Trust badges & security seals
- Test run by: [CZC.cz](https://liftarchive.com/practitioners/czc-cz/)
- Commentary by: LiftArchive (our analysis, not theirs)
- Original source: https://wingify.com/success-stories/czc/
- Page: https://liftarchive.com/test/czc-heureka-ratings-slide-in-left/

A slide-in bar of Heureka store ratings on the left side of product pages lifted revenue by 7.5% at 95% confidence. Czech electronics retailer CZC.cz ran the test, published as a VWO case study. It tested four placements, and the versions with a clickable badge under Add to Cart did worse.

## Result

**+7.5% revenue**

- Left slide-in ratings bar: +7.5% revenue at 95% confidence. This was the winner.
- Right slide-in ratings bar: no improvement in conversion rate.
- Badge versions under Add to Cart: did not win. Many visitors clicked the badge and left for the Heureka site.
- The badge inside the slide-in bars got no clicks, so those versions kept visitors on CZC.cz.

## Control

Product pages showed no Heureka badge or ratings. Heureka is a popular Czech price comparison site that collects store reviews.

## Variant

Four versions were tested: badge plus ratings below Add to Cart, badge only below Add to Cart, a slide-in ratings bar on the right, and a slide-in ratings bar on the left. Hovering over the slide-in bar showed rating details.

## Why it likely won (our reading)

- Czech shoppers are price-sensitive, and ratings from a well-known comparison site signal that the store is trustworthy.
- The left side sits in the normal reading path of the page, so the bar was seen. The right-side bar was easy to miss.
- A clickable badge near the buy button invited shoppers to leave and compare prices with competitors on Heureka.
- The hover detail let visitors check the ratings without leaving the page.

## Caveats

More than 90,000 visitors took part, but only half of site traffic was included in the test. Results are vendor-reported and no test dates were given.

## How to run this test

- Hypothesis: If we show third-party store ratings in a noticeable slide-in that does not link away, then revenue will rise because shoppers gain trust without leaving to compare prices.
- Primary metric: Revenue per visitor
- Guardrail: Exit rate to the ratings site
- Guardrail: Conversion rate
- Guardrail: Add to Cart rate
- Who should test it: Retailers in price-sensitive markets with good ratings on a well-known review or comparison site. If the review site lists your competitors, avoid outbound links near the buy button.

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Credit: CZC.cz ran this test and owns the result. Summary and commentary by LiftArchive (https://liftarchive.com/test/czc-heureka-ratings-slide-in-left/).
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.