·         Determine whether the campaigns are profitable, then test different target cost-per-acquisition (CPA) bid increases to see which maximizes total profit
·         Ad spend should always be 7% of revenue, which should be used as the target ROI
·         Decrease the target cost-per-acquisition (CPA) for the campaigns from US$15 to US$10 to drive an increase in profit per customer
·         The company’s email campaigns are the most profitable, with a cost-per-acquisition of US$15, so it should use that as a benchmark when setting target cost-per-acquisition (CPA) bids