Minimumdetectable effect
The smallest improvement a test is designed to be able to notice reliably.
Growth Score · Activation
Definition
What it means
The minimum detectable effect is chosen before a test starts and sets how much traffic it needs. Asking for a tiny lift on a small site means waiting months.
Testing bolder changes makes larger, easier-to-detect effects possible.
Activation
Why it matters, with an example
Choosing it before you start tells you whether your traffic can answer the question at all.
For example: A test built to notice a 5% relative lift needs far more visitors than one built to notice a 30% lift, so a small site should test bolder changes.
In Growth Score
Part of your score
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FAQ
Quick answers
What is Minimum detectable effect?
The smallest improvement a test is designed to be able to notice reliably.
Where does it sit in Growth Score?
It belongs to the Activation pillar, one of the 12 pillars your score is built from.
What should I read next?
Start with Sample size and Statistical significance, then browse the other terms in Activation.
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Growth Score reads your site and scores its Activation pillar against sites like yours.
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