How many adverts does the average person see in a day? If you search for this question online, the surprising answer is that we might see thousands – up to 10,000. However, the idea that we see thousands of adverts is a strange and confusing one, without any good research behind it. We investigate the long history of these odd numbers, with the help of Sam Anderson from The Drum and J Walker Smith from Kantar. Presenter: Tim Harford Series producer: Tom Colls Production co-ordinator: Brenda Brown Sound Mix: James Beard Editor: Richard Vadon