Heureka ratings slide-in on the left of product pages: +7.5% revenue
Commentary byLiftArchiveOur analysis, not theirsA 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.
- 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.
The change
The winner adds a Heureka ratings bar that slides in from the left.
Simplified mockup drawn by LiftArchive from the shared screenshots.
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 of the result, not the practitioner's claim.
- 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.
Who ran it
CZC.cz ran this test for CZC.cz and published the results (VWO case study). The numbers are theirs; the summary and commentary on this page are ours.
Read the original case study on CZC.cz →
How to run this test on your store
- 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
- Guardrails
- Exit rate to the ratings site
- Conversion rate
- 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.
Questions
Where should third-party review badges go on a product page?
In this test, a slide-in bar on the left beat badges under the Add to Cart button.
It was visible but did not pull shoppers off the site.
Can a review badge hurt conversions?
Yes, if it links to a site where shoppers can compare competitors.
CZC.cz saw many clicks on the badge near the buy button, and those versions did not win.
Does it matter which side of the page a trust element sits on?
It did here. The right-side bar showed no gain, likely because visitors read from the left and missed it.
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