Experimentation
Minimum detectable effect (MDE)
Also calledMDE
The smallest improvement a test is designed to reliably detect. Choosing it is a business decision about which changes are worth knowing about.
If a 1 per cent lift would not change your plans, there is no point running a test big enough to detect one. The MDE sets that line, and with it the sample size and duration of the test.
Low-traffic products have to accept larger MDEs, which means they can only reliably detect big changes. That is a reason to test bold ideas rather than small tweaks.