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'Anonymized' Credit Card Data Not So Anonymous, MIT Study Shows

Posted by timothy on from the why-I-order-from-the-women's-menu dept.

schwit1 writes Scientists showed they can identify you with more than 90 percent accuracy by looking at just four purchases, three if the price is included — and this is after companies "anonymized" the transaction records, saying they wiped away names and other personal details. The study out of MIT, published Thursday in the journal Science, examined three months of credit card records for 1.1 million people. "We are showing that the privacy we are told that we have isn't real," study co-author Alex "Sandy" Pentland of the Massachusetts Institute of Technology, said in an email.

2 of 96 comments (clear)

  1. "the privacy we are told that we have isn't real." by turkeydance · · Score: 4, Funny

    Staff Sergeant Obvious reporting for duty.

  2. Re:"the privacy we are told that we have isn't rea by ShanghaiBill · · Score: 3, Funny

    I always thought it was anonymized through aggregation.

    Aggregation is not very useful. Much more useful is being able to look for relationships between purchases by the same user. Years ago department stores would have an "accessories" section. Then Wal-Mart crunched their data, and figured out that people don't shop for accessories randomly. They buy a belt when they are buying pants. They buy a necktie when they are buying shirts. So today, the belts are placed by the pants, and the neckties are placed by the shirts. This seems kind of obvious in hindsight, but it took data analysis to make it happen.

    If a woman stops buying condoms and starts buying vitamin supplements, that means you should showing her popup ads for maternity clothes. Nine months later, you can show her a different brand of condom, with ads than emphasize reliability.