An efficient ROI model consists of three components: Cost per contact, percent of waste generated, and impact caused by the marketing format. Each individual media type has a different impact. TV reaches the majority of the population, but the Google Display Network has the lowest cost per GRP: 14 times less than TV, and five times less than radio. Our study found that GDN is 7.8 times more efficient than TV in driving visits to websites among over-15s.

February 2012