Measure cannibalization from a launch you can't A/B
Causal inferenceHardProblem. A new Echo model launched to everyone. You need to know how much it cannibalized the existing portfolio (vs created incremental demand). With no control, how do you measure it?
Before you reveal: say your answer out loud, as if you were in the real interview — get your reasoning across clearly first. There is no single correct answer: reading what the interviewer is really after and defending your own thinking is what makes an answer strong.