Whilst some commentators would argue this is a difficult task, the research exercise - carried out on 94 brands in a wide array of categories - showed that it is possible to quantify the long-term advertising impact on sales. In 83 out of the 94 brands examined, it has been possible to demonstrate the additional longer-term impact of advertising on sales.

Key findings include:

• The majority of these brands had a longer-term sales effect around the same or double the short-term impact.
  
• However, one in five had a longer-term advertising effect at least 5 times greater than the short-term impact.
  
• Advertising weight appears to be important. Brands with low ad weights or inconsistent spending patterns tended to have smaller long-term effects.
  
• Advertising builds sales momentum over the longer-term. Established brands displayed a greater ratio of long-term to short-term sales due to advertising. Newer brands had a higher ratio of ad sales accruing over the short-term as they built up their overall sales momentum.
  
• The creative element matters. Ads with better creative appear to have a larger and longer lasting long-term sales effect.