For nearly 100 years, roughly 1% of GDP has been invested in US advertising each year, with little deviation. A similar pattern occurs globally, with total ad spend falling between 0.6 and 0.9% of gross world product every year since 1980. Whether it was in convincing the public that ‘a diamond is forever’ or encouraging us all to ‘have a break, have a Kit Kat’, advertising has long played a pivotal role in shaping both popular culture and the fortunes of brands.
However, the question of whether it works continues to plague the industry, with a century-old quote about...