One of the few times you actually use a pen to write something down these days is just before a trip to the supermarket.
In order to understand how these rather charming, old-fashioned scribbles influence what actually makes it into our shopping baskets, Tesco data crunchers dunnhumby compared the shopping lists of 250 customers exiting six stores in and around London with what they actually bought.
The sample was small, but nevertheless revealed patterns about our habits.
Most people were vague in what they wrote down: 71 per cent specified neither the name of the product or the quantity. The top ten list items were:
- Milk
- Bread
- Eggs
- Potatoes
- Bananas
- Fruit
- Bacon
- Butter
- Juice
- Biscuits
And the top five unlisted items that were most bought were:
- Bananas
- Strawberries
- The Sun
- Carrots
- On the vine tomatoes
Britons are obviously bananas for bananas: fifth on the top ten list and the top impulse buy.
dunnhumby also looked at how the length of a shopping list correlated with the number of items people bought - and showed how rubbish we are at actually sticking to our lists.
If all customers bought everything on their list and nothing more, every dot on the graph below would be along the horizontal line 1. But the dots are scattered all over the place:
Those with short lists tend to buy more stuff (that’s any dot above the horizontal line 1) and those with longer lists fail to complete the list (any dot below the line). No surprises really, although perhaps the variation is larger than what you might expect.
There are many reasons we don’t to stick to our lists. We often change our minds once we are out the house, we get worried it’s all too expensive, we can’t find that fancy ingredient (damn you, Yotam!)…and sometimes the shop is simply out of milk and bread.
My latest book is Alex Through the Looking Glass (UK) and The Grapes of Math (US). To keep in touch with this blog I’m on Twitter, Facebook and Google+. Also, my personal website.
