Another interesting metric to look at is “number of users acquired over a specific time period.” Often, this will help you compare different marketing approaches — for example, a Facebook campaign in the first week, a reddit campaign in the second, a Google AdWords campaign in the third, and a LinkedIn campaign in the fourth. Segmenting experiments by time in this way isn’t precise, but it’s relatively easy.[7] And it’s actionable: if Facebook works better than LinkedIn, you know where to spend your money.
