What does your shopping history say about you?

According to the experts, just about everything

By Leah Ching

The Argus

photo by EP technology/ Flickr

For many, credit card safety isn’t a large concern as people put massive amounts of trust in their banks and the places they shop to protect their identity. CBC and a recent study by the Massachusetts Institute of Technology report that credit card data may not be anonymous as many think.

In fact, the study has shown that scientists can identify a person with over 90% accuracy just by looking at three or four items in one’s purchase history, even if companies wipe away names and personal details before presenting the transaction record. The intensive study examined records of over a million people over the course of three months.

The head scientist conducting the study showed that the anonymity that people may believe they have doesn’t truly exist with the world of credit cards. Outsiders often have access to credit card data from companies after personal information is “stripped,” but it doesn’t take much to identify the purchaser based on a few purchases. It’s quite alarming to consider how easily researchers were able to identify people based on their credit card history. In an example given, by looking at two purchases over the course of two days at a bakery and a restaurant, researchers were able to somehow find the one person that fit the purchases. The study then quoted “and we now know all of his other transactions, such as the fact that he went shopping for shoes and groceries on 23 September, and how much he spent.” How this is done, is extremely complex and uses large data sets and calculations, but the full journal can be accessed for free by anyone interested at sciencemag.org

For some reason the study also purported that women are easier to identify based on their purchases but the researchers couldn’t offer a solid hypothesis as to why this was so.  This may shock a lot of shoppers, but for those that study data and privacy, this comes as no surprise. Many people are unaware that companies they shop at routinely release “de-identified” transaction data and think it’s safe to do so. The multitude of ways in which this privacy gap affects the general public haven’t yet come to light, but the study purports some thought provoking information for consideration.

With the use of this kind of data rising in big companies, the aim is to acquire personal information about consumers through retail purchase history, online web browsing activity and other so called “digital breadcrumbs.” This collection occurs increasingly lately with the end goal being use in advertising and marketing campaigns. A little known fact is how purchaser information was used in the 2012 U.S. presidential candidate to seek out donors and voters. Companies are rapidly expanding their use of this type of data, called “metadata” and using it to pin point specific individuals. Questions to consider are how can this legal privacy breach be used in the future to target people when it comes to insurance applications, claims, loans and mortgage considerations and even divorce proceedings.

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