> First, the amount of profit per customer visit is not necessarily constant, and can depend on things such as gas prices
Given the scope of the company doing this kind of analysis, I don’t think variance is going to be significant. Given a large enough sample or pool of data, some kind of “regression to the mean” effect is going to kick in. Remember it is all “estimation” in the end anyways, and I can see the value in having some kind of observable data as opposed to data based on “honest” reporting by those you are trying to study.
Given the scope of the company doing this kind of analysis, I don’t think variance is going to be significant. Given a large enough sample or pool of data, some kind of “regression to the mean” effect is going to kick in. Remember it is all “estimation” in the end anyways, and I can see the value in having some kind of observable data as opposed to data based on “honest” reporting by those you are trying to study.