Shoppers Control Their Impulse Buys

February 23, 2010

No applause necessary.

No applause necessary. All the science and sweat that goes into presenting merchandise well on the retail sales floor – in both everyday sets and promotional displays – has less impact on incremental sales than many in the trade suspect.

Turns out that consumers are pretty efficient shopping planners after all, and they generally have enough discipline to resist most temptations in the aisles. A new academic study of shoppers in several Texas grocery stores found a minuscule difference between what they planned to spend on their latest trip and what they actually spent. The average budget deviation was less than a dollar, far less, a mere 47 cents.

Our reaction at This is a jolt. If true, it tells us the trade is failing horribly in its mission to attract extra purchases and build baskets. As a result of this study, we feel that retailers and CPG should collectively re-evaluate the data they depend on that keeps reinforcing the tale of success. It is, after all, data with an agenda to cement business relationships. Is it really objective? Are there flaws in the methodology? We all need to find out.

The researchers with no agenda but the truth may well be onto something. The full study, “Planning to Make Unplanned Purchases? The Role of In-Store Slack in Budget Deviation,” by Karen M. Stilley, Jeffrey Inman (both University of Pittsburgh) and Kirk L. Wakefield (Baylor University) will be released in the August 2010 issue of the Journal of Consumer Research.  

Their premise: Shoppers often expect to buy a certain number of unplanned items, and most have a good idea of how much they’ll spend on them. Their mental budgets for grocery shopping trips leave room for unplanned purchases – what the authors call ‘in-store slack.’

In their study, the researchers asked shoppers what items they planned to buy, how much they expected to spend on the planned items, and how much they expected to spend on the total trip. After shopping, respondents showed their receipts and answered questions about themselves and the shopping experience. More than three-quarters included room for unplanned purchases.

“They employ this strategy because they anticipate ‘forgotten needs’ and realize they’ll encounter ‘unplanned wants,” the authors write, noting that less-impulsive individuals use the ‘slack’ money without exceeding their mental budgets while more-impulsive individuals overspent if they shop most aisles.  For most consumers, in-store slack “appears to be a rational way to use the store to cue needs and preserve self-control,” they add.