The Truth About Impulse Buying

If you are anything like me you probably grew up thinking most of your purchases in a shopping-cart-on-handSupermarket were unplanned and that there were forces at work in Supermarkets compelling us to buy things we did not need. (rule number 1; don’t take kids shopping)

This was based on a number of studies, probably conducted by Supermarkets to support the high cost of end of aisle displays, but in his 1999 book “Why We Buy: The Science of Shopping“, psychologist and market researcher Paco Underhill described supermarkets “as places of high impulse buying…. Fully 60% to 70% of purchases there were unplanned, grocery industry studies have shown us.”

In a recent study, “Unplanned Category Purchase Incidence: Who Does It, How Often and Why,” Wharton marketing professor David R. Bell and two colleagues, Daniel Corsten, professor of operations and technology at the Instituto de Empresa Business School in Madrid, and George Knox, professor of marketing at Tilburg University in the Netherlands, argue that the amount of unplanned buying is closer to 20%.

I wonder how many other myths would be broken by new studies? Do 4 out of 5 dentists really recommend Crest still?  Id not why are we still buying it?

Their research does not indicate that in-store marketing is unimportant, but that retailers may need to rethink strategies for it. The researchers found that certain traits of shoppers, including age, income and their particular shopping style, have a greater effect on making unplanned purchases than does the store or environment.

What the researchers found missing in the previous studies was “appropriate and robust” data from actual purchases that would indicate what shoppers’ intentions were when they went to a store. The previous studies also did not clearly define “unplanned purchases” to Bell and his colleagues’ satisfaction. Does it mean switching brands of detergent from what a shopper usually buys, or buying any product from a category not on a shopping list? And if a shopping list included detergent but not a brand or size, is the final purchase planned or unplanned?

beer-on-display The starting point for Bell’s study, which was
partially funded by a large European consumer
products company, was a review of data from
2,945 supermarket shoppers over a two-week
period in July 2006. The consumers shopped at 21
different supermarkets, making 18,000 purchases
in 58 categories, such as bread, beer, coffee,
produce, detergent, diapers and shampoos and

The shoppers completed short questionnaires after
each trip, checking off purchases in a category and indicating whether a purchase was “planned in advance of the store visit” or simply “decided in store and purchased.” The shoppers attached their store receipts to ensure accuracy. More information on household traits and perceptions of the supermarkets where they shopped was gathered in 90-minute in-home interviews.

The questionnaire and the interviews provided Bell, Corsten and Knox with demographic data, including income bracket and life stage; “shopping style” information, including whether a shopper considered himself “fast and efficient”; and whether the shopper learned about prices from newspaper advertising or in the store. The respondents also were asked about their knowledge of a particular store and its prices, range of offerings and image; if they shopped on weekdays or weekends; and whether shopping trips were long or short.

Bell noted that American shoppers are different from their Dutch counterparts in at least one respect that may merit further study. While most Americans drive to a grocery store, people in the Netherlands are just as likely to walk or ride a bicycle as they are to drive. The researchers found that shoppers who walk to a market are less likely to make unplanned purchases than those who bike or drive.

The most basic information the research revealed is that no unplanned buying was done on slightly more than 60% of all shopping trips. On the rest of the trips, the shoppers made an average of three unplanned purchases — far fewer than previous research indicated.

The amount of unplanned buying goes up with the total number of categories in which shoppers make purchases, such as bread or milk. But because a smaller percentage of shoppers are doing much of the impulse buying, the average number of unplanned purchases stays low.

More telling data about what makes shoppers behave as they do came from correlating 32 variables with the fact that the majority of all shopping trips include no unplanned purchasing. Here are some of the variables compared with the overall average:

  • Young, unmarried adult households with higher incomes do 45% more unplanned buying.
  • Households led by an older person and those that have larger families do 31% to 65% less spontaneous purchasing.
  • There is 25% less unplanned buying among shoppers who mainly use newspaper ads for price information.
  • People who consider themselves very “fast and efficient” shoppers are far less likely to make impulse buys — 82% less than the average.
  • If the purpose of a shopping trip is “immediate needs or forgotten items,” the rate of buying in unplanned categories falls by 53%.
  • Unplanned purchasing goes up by 23% if the shopping trip itself is unplanned, but it goes down by 13% if it’s a major or weekly trip.
  • If a shopping trip includes stops at multiple stores, there is 9% less unplanned buying at the second or third store.
  • Unplanned purchasing goes up by 44% if the shopper goes to the store by car instead of on foot.

“The message … is that the amount of unplanned buying that takes place is more about person-to-person variance than about the store environment itself,” Bell says. “Can you really jack up unplanned buying with stimuli, when the greatest amount of variance is in people?”

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