Despite confirming to Facebook in January 2016 that it had deleted the data it had obtained of millions of Facebook users, Cambridge Analytica kept information based on that data until 2017, reports the Guardian. While the original data was deleted, Cambridge Analytica kept derivatives of that data. Data derivatives are often much more valuable than the original raw data itself, as they can contain predictive models or psychological groupings of users in a data set. It is from these data derivatives that ads can be micro-targeted at users along psychological lines, as Cambridge Analytica at times purported to do for the Ted Cruz and Donald Trump campaigns.
The retention of the data derivatives is troublesome. Mark Zuckerberg told Congress that Cambridge Analytica “represented to us” that it has deleted all data models based on the original raw data of Facebook users in 2016, while Cambridge Analytica’s lawyers had previously said the data had been erased by September 2016. So why do emails the Guardian obtained now show data derivatives existed until April 2017?
Cambridge Analytica had previously claimed to have profiles on hundreds of millions of U.S. voters, in order to target ads at them during elections and commercial campaigns, but recently the firm has said that those profiles were not built on Facebook data. Many have questioned that claim. As we previously reported, Facebook’s investigation into the pilfered data—and its lawyer’s demands that data be deleted—appeared to be ongoing as of April 2017. That was the same month that The Intercept reported some of the details of Cambridge Analytica’s operation.
The retention of the data models by Cambridge Analytica at least through April 2017 is salient to the data protection of all U.S. voters, according to David Carroll, a professor at the Parsons School of Design in New York. On Saturday, investigators in the U.K. determined that after a legal claim against the firm by Carroll, it would need to turn over more details of the data it used to compile his voter profile.
Though the firm announced last week it was entering bankruptcy proceedings—amid reports that its executives were moving their operations to a new brand, Emerdata—the firm will still be compelled to comply with legal claims. Failure to comply with the order about Carroll’s data, said Information Commissioner Elizabeth Denham, “is a criminal offense, punishable in the courts by an unlimited fine.”
Facebook also has more questions to answer, including why it did not do a better job of certifying that the data and its derivatives had been deleted. The question is particularly pertinent since Facebook employees on its election ads team worked inside the Trump campaign’s digital headquarters, on what turned out to be the highest-spending political campaign in Facebook’s history. —with Alex Pasternack
Related: How Facebook Blew It