Household panels are probably as good it gets for understanding who buys what. Assuming the people on the panel scan in everything they bring home. Assuming the people on the panel are representative of the “universe”.

But what about all the products people buy (and consume) but don’t bring home? For years this has plagued the market research industry. For example, so much Coke is bought outside the home but there is now way of tracking it apart from looking at HoReCa sales (Hotels, Restaurants and Catering). But the data tells you nothing about WHO bought.

Enter GfK’s latest idea. Join their panel and tell them what you buy out of the home by mobile, in return for a small reward. It’ll be interesting to see if it works (according to their website enough people have now registered) …