2 min lesson
Incrementality is the only honest question
Explain the order in "Incrementality is the only honest question", then say how you would verify the result.
Step 1 of 2
Incrementality is the only honest questionwhat the program actually caused
Correlation asks "did leads who touched the program convert more?" Incrementality asks "would they have converted anyway?" The second is harder and far more valuable. The cleanest evidence is a holdout: a comparable group that didn't get the program, measured against the group that did.
Interactive diagram. Tab through its regions; each focused region shows its detail in the panel below.
diagram: stack
Each rung rests on the one below; name the rung your number actually stands on.