Incrementality Testing is a proven experimental approach for measuring the incremental contribution of media. Tests are executed by systematically withholding ad exposure to a representative subset,  or “cohort,” of the target audience (the control group) while maintaining normal ad exposure to the broader audience set (the test group). As long as the control group is selected at random and sizable enough to be statistically significant, then the incremental contribution of the media can be determined by the difference in performance results (conversion, revenue, profitability, etc.) between the test and control groups.