After one month of banner advertising on the internet the French Supermarket chain Carrefours experienced a 6 % growth in turnover.
This was revealed by a major study conducted by the french Interactive Advertising Bureau (IAB) presented Friday in London at the IAB Europe leadership council which I attended as head of the Danish IAB, the FDIM.
The methodology of the French study is apparently very convincing.
On the one hand all internet activity in a panel of 1200 people in two middlesized french towns, Le Mans and Angers, were registered by a piece of software the panellists had installed on their computers.
On the other all members of the panel had their purchases in the Carrefour supermarket registered by means of special bonus cards used by the panellists when shopping at Carrefour.
The study therefore was able to compare panellists who had been exposed to the banner ads to those who had not. Interesting details of the study is that the increase was due to an increase in the spending of existing customers. That the size of the customers shopping basket remained constant while the number of visits to the stores increased. And that a minimum of 7 exposures were required to yield results.
Read more about the case in this press release from IAB France (in french).