Welcome to your interview.
The question is on your right: Direct Mail Incremental Lift Design. Take a moment with it first.
Talk your thinking through with me if you like - when you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes). Discussion and graded submissions share your five interviewer interactions, so spend them well.
For a direct mail campaign at Ledgent Technology, how do you determine the optimal list size, test cells, and control groups to measure true incremental lift?