You get the same sneaking suspicion every time you book a hotel or rent a car online: With each search, it seems the prices change, and you can’t help but wonder if sites are changing prices for you in particular.
Well, they are—at least in some ways.
A team of researchers at Northeastern University recently analyzed how e-commerce sites tailor prices to specific shoppers based on their digital habits and demographics, such as their ZIP code. According to the study, presented last week at the Internet Measurement Conference in Vancouver, major e-commerce sites including Home Depot, Walmart, and Hotels.com list online prices that are all over the map, and in some cases, these prices are “personalized” to the behavior of particular shoppers, including whether they shop on a phone or on a desktop.
“Going into this, we assumed the project would be risky—that we might not find anything,” says Christo Wilson, an assistant professor of computer science at Northeastern and one of the study’s authors. “There have been incidents in the past where companies have been caught doing this, and the PR was very bad. We thought that sites wouldn’t be doing anything. We were more surprised that we found something.”
According to some companies whose sites were analyzed by the study, its methodology was flawed—and the researchers have admitted to one mistake in the way they handled things. But the study still provides a window into how your shopping experience can change depending how you behave.
Mobile Matters
The researchers recruited 300 people through the crowdsourcing site Mechanical Turk and had them perform product searches on 16 top e-commerce sites. Specifically, the study tested for personalization based on browser (Chrome, IE, Firefox, Safari), operating system (Windows, OS X, iOS, Android), and whether or not a user was logged into his or her online account.
As each person ran the searches—with long browsing histories attached to identifying “cookies” on their machines—an automatic, cookie-less simulated browser ran the same searches at exactly the same time. This, says Wilson, ensured that price differences couldn’t be chalked up to “noise” or variations in timing that might reflect an inventory change or other quirk of the system.
If you shop using your smartphone, the study claims, some e-commerce sites pay attention to what kind of phone you use. Home Depot and Travelocity—whose sites were targeted by the study—deny that they do this, and Travelocity pointed out a flaw in the study’s methodology, which the researchers have since admitted to.
