Minimum Detectable Effect

Minimum detectable effect (MDE) is a statistical characteristic of each experiment you design.

This number indicates the percent change that must be caused by one of your variants in order for the experiment to reach a conclusive result.

In general:

  • Lower MDE → experiments reach statistical significance faster
  • Lower MDE → more experiments yield conclusive results
  • Fewer variants → lower MDE
  • A higher baseline conversion rate → lower MDE