Skip to content
Hosted in Europe. Your test data is stored in the European Union.Hosted and stored in EuropeLearn more

Your completed tests become learnings.

Winner, loser, or no detectable effect, every completed test joins the library with its effect and what the team learned from it. Effects are compared on one scale, and are used to estimate the next tests.

Learning · shipping
high confidence4 tests · 3 winners

Reassuring shoppers about shipping pays off.

Showing shipping costs early, highlighting free returns, and lowering the free-shipping threshold beat the original by +2.1% to +5.8%. Pooled effect: +2.5%, between +1.3% and +3.6%.

Completed tests378 winners · 6 losers · 23 with no detectable effect
0:39 · no sound, looping
Read the transcript

What’s left once a test ends? Every completed test joins the library, and the engine uses it to judge the next ones.

Every effect on the same scale. The demo’s 37 completed tests, in the order they ended. Most effects are small: median +0.9%.

Lessons by theme, with their confidence. A lesson needs at least three tests on the same theme. Its confidence is high when their pooled effect excludes zero.

What was tested, where, and when. One row per zone of the journey: Product page had 16, Category page just one, still running. Hollow bars are tests still running.

It corrects the next winners. From these 48 effects, the engine derives a prior: mean +1.7%, spread 3.4%. A winner measured at +6.0% is reported at +4.9%.

The demo library already holds 37 completed tests. Open it, no sign-up needed.

Every effect, on one scale.

The demo store’s 37 completed tests since December 2025. Most effects are small (median +0.9%), which is why winners need to be corrected.

-6%-4%-2%0%+2%+4%+6%+8%median +0.9%winners +3.7%Checkout in four numbered steps : -4.2% (loser)Strikethrough prices in red : -3.4% (loser)Mega menu with photos : -2.9% (loser)“Only 3 left in stock” message : -2.7% (loser)Gift wrapping offered in the cart : -2.4% (loser)Home page carousel replaced with a grid : -2.2% (loser)Mood video at the top of the home page : -1.4% (no detectable effect)Product video in first position : -1.2% (no detectable effect)Related products under the buy button : -1.1% (no detectable effect)Sale banner at the top of the home page : -0.8% (no detectable effect)Sorting cut to three options on mobile : -0.6% (no detectable effect)Savings shown in the cart : -0.3% (no detectable effect)One product per row on mobile : -0.2% (no detectable effect)Breadcrumbs on category pages : +0.3% (no detectable effect)Dimensions shown on the photo : +0.4% (no detectable effect)Countdown timer on flash sales : +0.5% (no detectable effect)Secure payment badges : +0.6% (no detectable effect)Top categories as thumbnails : +0.7% (no detectable effect)Fewer product options shown on mobile : +0.9% (no detectable effect)Address autocomplete : +0.9% (no detectable effect)Fewer form fields : +1.0% (no detectable effect)Search suggestions : +1.1% (no detectable effect)Bigger product photos : +1.1% (no detectable effect)Delivery time shown in the cart : +1.2% (no detectable effect)New arrivals featured on the home page : +1.3% (no detectable effect)Search bar always visible on mobile : +1.4% (no detectable effect)Cart in a side panel : +2.3% (no detectable effect)Average rating under the title : +2.6% (no detectable effect)Complementary products in the cart : +3.1% (no detectable effect)Promo code field collapsed : +1.8% (winner)Shipping costs shown on the product page : +2.1% (winner)Sticky buy button on mobile : +2.5% (winner)Free returns highlighted : +3.4% (winner)Simplified filters on mobile : +4.0% (winner)Simplified order summary : +4.1% (winner)Free shipping from €60 : +5.8% (winner)Guest checkout : +7.3% (winner)-6%-4%-2%0%+2%+4%+6%+8%median +0.9%winners +3.7%Checkout in four numbered steps : -4.2% (loser)Strikethrough prices in red : -3.4% (loser)Mega menu with photos : -2.9% (loser)“Only 3 left in stock” message : -2.7% (loser)Gift wrapping offered in the cart : -2.4% (loser)Home page carousel replaced with a grid : -2.2% (loser)Mood video at the top of the home page : -1.4% (no detectable effect)Product video in first position : -1.2% (no detectable effect)Related products under the buy button : -1.1% (no detectable effect)Sale banner at the top of the home page : -0.8% (no detectable effect)Sorting cut to three options on mobile : -0.6% (no detectable effect)Savings shown in the cart : -0.3% (no detectable effect)One product per row on mobile : -0.2% (no detectable effect)Breadcrumbs on category pages : +0.3% (no detectable effect)Dimensions shown on the photo : +0.4% (no detectable effect)Countdown timer on flash sales : +0.5% (no detectable effect)Secure payment badges : +0.6% (no detectable effect)Top categories as thumbnails : +0.7% (no detectable effect)Fewer product options shown on mobile : +0.9% (no detectable effect)Address autocomplete : +0.9% (no detectable effect)Fewer form fields : +1.0% (no detectable effect)Search suggestions : +1.1% (no detectable effect)Bigger product photos : +1.1% (no detectable effect)Delivery time shown in the cart : +1.2% (no detectable effect)New arrivals featured on the home page : +1.3% (no detectable effect)Search bar always visible on mobile : +1.4% (no detectable effect)Cart in a side panel : +2.3% (no detectable effect)Average rating under the title : +2.6% (no detectable effect)Complementary products in the cart : +3.1% (no detectable effect)Promo code field collapsed : +1.8% (winner)Shipping costs shown on the product page : +2.1% (winner)Sticky buy button on mobile : +2.5% (winner)Free returns highlighted : +3.4% (winner)Simplified filters on mobile : +4.0% (winner)Simplified order summary : +4.1% (winner)Free shipping from €60 : +5.8% (winner)Guest checkout : +7.3% (winner)
Winner Loser No detectable effectOne dot per completed test, at its relative effect on its primary metric. Demo store.
See all 37 tests
TestAreaMetricEffectResult
Guest checkoutCheckoutConversion+7.3%winner
Free shipping from €60CartRevenue per visitor+5.8%winner
Simplified order summaryCartConversion+4.1%winner
Simplified filters on mobileNavigationProduct click+4.0%winner
Free returns highlightedProduct pageRevenue per visitor+3.4%winner
Complementary products in the cartCartRevenue per visitor+3.1%no detectable effect
Average rating under the titleProduct pageAdd to cart+2.6%no detectable effect
Sticky buy button on mobileProduct pageAdd to cart+2.5%winner
Cart in a side panelCartConversion+2.3%no detectable effect
Shipping costs shown on the product pageProduct pageRevenue per visitor+2.1%winner
Promo code field collapsedCartConversion+1.8%winner
Search bar always visible on mobileNavigationProduct click+1.4%no detectable effect
New arrivals featured on the home pageHome pageProduct click+1.3%no detectable effect
Delivery time shown in the cartCartConversion+1.2%no detectable effect
Bigger product photosProduct pageAdd to cart+1.1%no detectable effect
Search suggestionsNavigationProduct click+1.1%no detectable effect
Fewer form fieldsCheckoutConversion+1.0%no detectable effect
Address autocompleteCheckoutConversion+0.9%no detectable effect
Fewer product options shown on mobileProduct pageAdd to cart+0.9%no detectable effect
Top categories as thumbnailsHome pageProduct click+0.7%no detectable effect
Secure payment badgesCheckoutConversion+0.6%no detectable effect
Countdown timer on flash salesProduct pageRevenue per visitor+0.5%no detectable effect
Dimensions shown on the photoProduct pageAdd to cart+0.4%no detectable effect
Breadcrumbs on category pagesNavigationProduct click+0.3%no detectable effect
One product per row on mobileNavigationProduct click-0.2%no detectable effect
Savings shown in the cartCartRevenue per visitor-0.3%no detectable effect
Sorting cut to three options on mobileNavigationProduct click-0.6%no detectable effect
Sale banner at the top of the home pageHome pageProduct click-0.8%no detectable effect
Related products under the buy buttonProduct pageAdd to cart-1.1%no detectable effect
Product video in first positionProduct pageAdd to cart-1.2%no detectable effect
Mood video at the top of the home pageHome pageProduct click-1.4%no detectable effect
Home page carousel replaced with a gridHome pageProduct click-2.2%loser
Gift wrapping offered in the cartCartConversion-2.4%loser
“Only 3 left in stock” messageProduct pageAdd to cart-2.7%loser
Mega menu with photosNavigationProduct click-2.9%loser
Strikethrough prices in redProduct pageRevenue per visitor-3.4%loser
Checkout in four numbered stepsCheckoutConversion-4.2%loser

What the library draws from them.

Tests are grouped by cross-cutting theme (shipping, promotions, mobile choices…), whatever page was tested.

Learnings are read by theme, with their confidence.

For each theme, Probant pools the tests’ effects, weighting them by their precision. Confidence is “high” when, with at least 3 tests, the pooled effect’s range excludes zero; “low” below 3 tests, whatever their result. Only a high-confidence learning states a direction; the others stay “Not conclusive yet…”, with no concluding title.

  • Reassuring shoppers about shipping pays off. 4 tests · 3 winners, high confidence
  • Fewer choices on mobile: still to be confirmed. 5 tests · 2 winners, medium confidence
  • Highlighted promotions: no proven gain. 3 tests · 1 loser, medium confidence
shipping · 4 tests · 3 winnershigh confidence
Reassuring shoppers about shipping pays off.
mobile choices · 5 tests · 2 winnersmedium confidence
Fewer choices on mobile: still to be confirmed.
promotions · 3 tests · 1 losermedium confidence
Highlighted promotions: no proven gain.

The timeline shows what was tested, where, and when.

One row per area of the journey, from the home page to checkout. Running tests appear too, so you can see at a glance which areas are crowded and which no test has touched yet.

Timelineby area of the journey
Home page
Navigation
Category page
Product page
Cart
Checkout

It feeds the winner correction and idea estimates.

All past effects together give the engine a realistic prior: +1.7% on average, with a spread of 3.4%. It is what brings a winner measured at +6.0% down to +4.9% reported, and what provides the expected effect of an idea with no precedent.

What the library provides48 completed tests
Average test effect+1.7%spread 3.4%
Free shipping progress bar: reported difference+6.0% → +4.9%corrected for the winner’s curse
Idea in the “shipping” theme+2.5%pooled effect of 4 tests
Idea with no precedent+1.7%prior from the whole library
Prior on effectscentered on +1.7%

In detail.

What a test holds
Name, area, themes, dates, primary metric, effect and range, result, decision (rolled out, original kept, abandoned), and what the team learned, in one sentence.
Result
Computed by the engine, as for a running test, and always read with its metric: winner, loser, or no detectable effect. A test with a sample ratio mismatch appears as “skewed measurement”, excluded from learnings and priors.
Write-up
Drafted by Probant from the report, with the same figures: the measured and corrected differences each named, and no direction claimed when the range includes zero. The team reviews it, edits it, and publishes it to the library.
Imported tests
Tests from AB Tasty, VWO, Kameleoon, Optimizely, Convert, or GrowthBook join the list with their tool’s name, recalculated from their raw data; they count toward the quality score and the priors.
In the test plan
A new test’s target effect is placed among the effects of completed tests: realistic, ambitious, or never measured in the store.
Sharing and export
“Invite as viewer” creates an invitation for a member with the Viewer role; the CSV export includes the list, with effects in percentage points, and every export is recorded in the audit log.
Pooled effect
Average of the theme’s effects weighted by the inverse of their variance, with its range.
Confidence
Low below 3 tests; high if the pooled effect excludes zero; medium otherwise.
Prior
Mean and spread of true effects, estimated across all completed tests (48 in the demo), accounting for each one’s uncertainty.
Search
Across names, areas, themes, and what the team learned, ignoring accents, even phrased as a question (“What have we tested on pricing?”); a link to the library can carry its question.

Frequently asked questions.

Why keep tests with no detectable effect?

Because they show what doesn’t work, and they weigh in the prior: without them, the engine would assume effects are bigger than they are. In the demo, 23 of 37 tests have no detectable effect.

What happens at first, when the library is empty?

Learnings and the expected effect of ideas appear as tests complete. It takes at least three tests on the same theme to draw a learning.

Next: Installation and integrations

See this feature in the demo, on the screen this page describes, or move on to the next one.

  • Open demo, no sign-up
  • Free to start, no overage charges
  • Database and compute in Amsterdam, with Scaleway