What percentage of decisions do you think are made in-store? 75%? 70%? 40%? If you’ve got a vested interest, you’ll probably plump for whichever number suits your purposes best. If you’re an innocent bystander, then the chances are that you’re very confused.

So, to ask yet another question, does it really matter? After all, arbitrary ‘statistics’ are quoted as facts for all sorts of reasons every day. Some of these are meant to be manipulative but many are based on simple misapprehension or error.

However, this particular clutch is downright dangerous. It bears no relation to the complex realities of shopper behaviour that it supposedly seeks to describe; instead it reflects a widespread and profound confusion about the nature of shopper decision-making.

Let’s get a fundamental fallacy out of the way first. Shoppers’ decisions, whether in-store, at home or on the Clapham omnibus, aren’t based on the decision tree model. Despite the traditional approach to category management, merchandising and marketing, real-life people don’t behave like this at all.

The fact is that, however exciting industry insiders may find them, shoppers themselves are pretty bored by most categories. This means that the typical shopper has very low involvement with the vast majority of categories so spends very little time thinking about them or interacting with them.

In reality, purchases from all but a few categories are habituated. The majority of shoppers buy the same things every week, fortnight or month without fail. So when they got to the store, they know where the categories are and where, within them, their familiar items are. There is little or no active decision making in-store.

I can’t stress enough how important this is.  The traditional approach to in-store activation is based on the canard of widespread in-store decision making. But it’s time that we abandoned ill-advised attempts to influence shoppers’ at-fixture decisions – ‘buy this instead of that’ – and instead developed strategies that aim to develop different scripted behaviours.

As well as shopper marketing, this has fundamental implications for new product development, packaging, 360° marketing, promotions and advertising. It means that we need to go back to basics, examining the very purpose of our marketing strategy and asking ourselves precisely what our persuasion is trying to achieve.

None of this is to undermine the importance of the store or deny that it is the new battleground. It’s now generally accepted – certainly by readers of this magazine – that the influence of mass advertising is dwindling in the face of increasing media fragmentation and that shoppers constitute an audience. In-store activity is crucial for success in the drive to build brands through the line.

But we really do need to leave misinformation behind us and get wise to how shoppers use the store. By understanding why shoppers buy – and how their choices are influenced by the interplay of rational reasoning, emotions and memories – we can gain genuine influence over their purchasing decisions. The challenge for the in-store community, along with brands, retailers and other marketers, is to develop in-store activation based on a true understanding of shopper behaviour. Their rewards will be seen on the bottom line.

Siemon Scamell-Katz is Founder of TNS Magasin, the international shopper strategy consultancy.  This article first appeared in DDR, April /May 2009, issue 2, volume 6.