Measuring how a specific marketing event (e.g., site conversion) was causally influenced by a media channel or tactic, in this case display, over a set time period and budget to isolate the impact of a particular (digital) advertising tactic on sales. This methodology involves serving a PSA placement to a control group and a branded ad to the test / exposed group) and comparing the results. For this approach, if the control group is randomly selected, both groups should be behaviorally, demographically, and psychologically similar with the only difference between the groups being which ad they viewed.