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What effects can you expect from A/B tests?

Actively updated insights from 650 A/B tests :)


Small or Big

Small Tests

+2.7%

Generic Median Effect

(650 tests)

Big Tests

+13.5%

Generic Median Effect

(50 tests)

The smaller experiments are all sourced from GoodUI and are typically more "isolated" towards a single pattern (with occasional confounding). The bigger experiments are ones which combined as many multiple and positive probability changes into a single variation. These have been sourced from larger optimization projects we've designed and a/b tested over the years.


Adding, Replacing or Removing

Adding

+2.1%

Generic Median Effect

(298 tests)

Replacing

+3.7%

Generic Median Effect

(314 tests)

Removing

+2.7%

Generic Median Effect

(35 tests)


Desktop or Mobile

Desktop Only

+2.6%

Generic Median Effect

(512 tests)

View Desktop Patterns

Mobile Only

+2.7%

Generic Median Effect

(436 tests)

View Mobile Patterns

Desktop + Mobile

+2.7%

Generic Median Effect

(641 tests)

View All Patterns

By Change Types

Form

+2%

Generic Median Effect

(95 tests)

View Form Patterns

Headline

+4.3%

Generic Median Effect

(17 tests)

View Headline Patterns

Pricing

+4%

Generic Median Effect

(56 tests)

View Pricing Patterns

Popup

+1.3%

Generic Median Effect

(14 tests)

View Popup Patterns

Personalization

+2.6%

Generic Median Effect

(14 tests)

View Personalization Patterns

Layout

+5.5%

Generic Median Effect

(39 tests)

View Layout Patterns

Button

+2.4%

Generic Median Effect

(88 tests)

View Button Patterns

Photos

+2.4%

Generic Median Effect

(57 tests)

View Photos Patterns

Copy

+2.7%

Generic Median Effect

(209 tests)

View Copy Patterns

Interaction

+2.1%

Generic Median Effect

(129 tests)

View Interaction Patterns

Social Proof

+1.4%

Generic Median Effect

(49 tests)

View Social Proof Patterns

By Screen Types

Home & Landing

+6%

Generic Median Effect

(144 tests)

View Home & Landing Patterns

Content

+7.3%

Generic Median Effect

(11 tests)

View Content Patterns

Product

+2.5%

Generic Median Effect

(185 tests)

View Product Patterns

Checkout

+0.3%

Generic Median Effect

(70 tests)

View Checkout Patterns

Listing

+2.9%

Generic Median Effect

(90 tests)

View Listing Patterns

Thank You

+9.1%

Generic Median Effect

(4 tests)

View Thank You Patterns

Shopping Cart

+3.2%

Generic Median Effect

(24 tests)

View Shopping Cart Patterns

Signup

+2.4%

Generic Median Effect

(73 tests)

View Signup Patterns

Pricing

+4.9%

Generic Median Effect

(22 tests)

View Pricing Patterns

Global

+3.8%

Generic Median Effect

(23 tests)

View Global Patterns

By Metric Types

Progression

+7.6%

Generic Median Effect

(342 tests)

View Progression Patterns

Leads

+5.1%

Generic Median Effect

(123 tests)

View Leads Patterns

Signups

+2.9%

Generic Median Effect

(98 tests)

View Signups Patterns

Sales

+2.1%

Generic Median Effect

(390 tests)

View Sales Patterns

Engagement

+0.5%

Generic Median Effect

(14 tests)

View Engagement Patterns

Revenue

+5%

Generic Median Effect

(36 tests)

View Revenue Patterns

Statistical Power

Share of tests with 80% power at each MDE (608 of 650 tests with binary metric data)

1% MDE

1.6%

(10 tests)

2% MDE

4.4%

(27 tests)

5% MDE

25.8%

(157 tests)

10% MDE

48.5%

(295 tests)

15% MDE

61.7%

(375 tests)

Median MDE

10.3%

Detectable at 80% Power

Average Sample

250,527

Visitors (A+B)

Median Sample

34,606

Visitors (A+B)

Power is the chance a test would detect a true relative effect of the given size (minimum detectable effect, MDE) as significant, using a two-tailed test at α = 0.05. It's calculated from each test's visitor counts and control conversion rate on its primary metric. Tests without visitor data or with continuous metrics (such as revenue) are excluded.