Shoppers don't spend how they want to: Here's why

Online sales growth was red-hot this holiday; but could it have been even hotter?

According to a new report by the IBM Institute for Business Value, there's a widening gap between how consumers say they prefer to shop and how they actually make purchases.

The study, released Tuesday at the National Retail Federation's annual convention, found that although 43 percent of consumers said they preferred to shop online, only 29 percent actually made their last purchase digitally.

e-commerce online shopping
Johnnie Davis | Getty Images

That's up from last year, when 40 percent said they prefer to shop online, and 28 percent had made their last purchase through the channel.

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"We think it has something to do with consumer expectations," said Lance Tyson, senior retail consultant for IBM's Global Business Services unit.

Tyson said apps that operate in real time, such as Uber, have caused consumers to have greater demands for retailers' online offerings. One thing that's particularly frustrating for shoppers, he said, is when they find an item online but it isn't in stock when they arrive at the store.

Tracking the outlook of retail in 2015
Tracking the outlook of retail in 2015   

According to the study, 60 percent of respondents said it's important to be able to check if an item is in stock before they visit a retailer's physical location. What's more, 46 percent said it's important that employees can use mobile devices to fix out-of-stock issues. In other words, if the item isn't in that particular store, the sales associate should be able to fulfill their order from the Web or another location. That's up six points from last year.

"As consumer expectations for product fulfillment are shaped by online shopping experiences, out-of-stock situations are becoming less acceptable," the report said.

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IBM's study comes a few days after comScore said that shoppers spent a record $53.3 billion on desktop computers over the holidays, a 15 percent increase over the prior year. Furthermore, the firm expects mobile sales will add 1 to 2 percentage points to this growth rate.

IBM drew its results from four years of survey data from more than 110,000 consumers in 19 countries. The company markets its technology for use in the retail industry.