It IS confusing and there isn’t much of a discussion about the two (from what I read in the lesson). Plus, it would be super helpful if there was a cheatsheet! (IMO).
No, they’re different.
Lift is your desired conversion rate as calculated from your baseline.
Let’s say your baseline conversion rate for your site is currently 20% and you want to increase that by changing something on your website (or in a marketing campaign, etc.) to 22%.
So, 22%-20% = 2% lift in conversion.
Your MDE is calculated as a percent of the baseline and it’s the amount of effort you need to put forth to arrive at the desired change, or, lift.
MDE = desired conversion rate lift / baseline conversion rate x 100%
So, 2% / 20% = 10% MDE for your experiment.
The MDE is used when designing the A/B test and is the minimum improvement you’d like to see in your hypothesis test.
" The simplest way to think of MDE is the following – it is essentially the smallest possible change in your primary KPI that your experiment can detect with statistical certainty ."
From here: https://www.brooksbell.com/resource/blog/minimum-detectable-effect/
Maybe someone else can chime in if I’m not correct or explaining it well enough?