 Once they merged the gigantic data set of product sales with the gigantic data set of ad spending, Tuchman and her colleagues used an analytical method similar to the one she'd used to study e-cigarette sales. That is, they looked at bordering advertising markets that received different ads, and then using a few different models, they compared product sales for 212 of the top 500 consumer brands. And what'd they find? This might sound familiar.