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.
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%.
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.
See all 37 tests
| Test | Area | Metric | Effect | Result |
|---|---|---|---|---|
| Guest checkout | Checkout | Conversion | +7.3% | winner |
| Free shipping from €60 | Cart | Revenue per visitor | +5.8% | winner |
| Simplified order summary | Cart | Conversion | +4.1% | winner |
| Simplified filters on mobile | Navigation | Product click | +4.0% | winner |
| Free returns highlighted | Product page | Revenue per visitor | +3.4% | winner |
| Complementary products in the cart | Cart | Revenue per visitor | +3.1% | no detectable effect |
| Average rating under the title | Product page | Add to cart | +2.6% | no detectable effect |
| Sticky buy button on mobile | Product page | Add to cart | +2.5% | winner |
| Cart in a side panel | Cart | Conversion | +2.3% | no detectable effect |
| Shipping costs shown on the product page | Product page | Revenue per visitor | +2.1% | winner |
| Promo code field collapsed | Cart | Conversion | +1.8% | winner |
| Search bar always visible on mobile | Navigation | Product click | +1.4% | no detectable effect |
| New arrivals featured on the home page | Home page | Product click | +1.3% | no detectable effect |
| Delivery time shown in the cart | Cart | Conversion | +1.2% | no detectable effect |
| Bigger product photos | Product page | Add to cart | +1.1% | no detectable effect |
| Search suggestions | Navigation | Product click | +1.1% | no detectable effect |
| Fewer form fields | Checkout | Conversion | +1.0% | no detectable effect |
| Address autocomplete | Checkout | Conversion | +0.9% | no detectable effect |
| Fewer product options shown on mobile | Product page | Add to cart | +0.9% | no detectable effect |
| Top categories as thumbnails | Home page | Product click | +0.7% | no detectable effect |
| Secure payment badges | Checkout | Conversion | +0.6% | no detectable effect |
| Countdown timer on flash sales | Product page | Revenue per visitor | +0.5% | no detectable effect |
| Dimensions shown on the photo | Product page | Add to cart | +0.4% | no detectable effect |
| Breadcrumbs on category pages | Navigation | Product click | +0.3% | no detectable effect |
| One product per row on mobile | Navigation | Product click | -0.2% | no detectable effect |
| Savings shown in the cart | Cart | Revenue per visitor | -0.3% | no detectable effect |
| Sorting cut to three options on mobile | Navigation | Product click | -0.6% | no detectable effect |
| Sale banner at the top of the home page | Home page | Product click | -0.8% | no detectable effect |
| Related products under the buy button | Product page | Add to cart | -1.1% | no detectable effect |
| Product video in first position | Product page | Add to cart | -1.2% | no detectable effect |
| Mood video at the top of the home page | Home page | Product click | -1.4% | no detectable effect |
| Home page carousel replaced with a grid | Home page | Product click | -2.2% | loser |
| Gift wrapping offered in the cart | Cart | Conversion | -2.4% | loser |
| “Only 3 left in stock” message | Product page | Add to cart | -2.7% | loser |
| Mega menu with photos | Navigation | Product click | -2.9% | loser |
| Strikethrough prices in red | Product page | Revenue per visitor | -3.4% | loser |
| Checkout in four numbered steps | Checkout | Conversion | -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
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.
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.
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.
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