Paul Lewis

Facebook’s failure to compel Cambridge Analytica to delete all traces of data from its servers – including any “derivatives” – enabled the company to retain predictive models derived from millions of social media profiles throughout the US presidential election, the Guardian can reveal. Leaked emails reveal that when Cambridge Analytica told Facebook almost a year before the election that it had deleted data harvested from tens of millions of Facebook users, it stopped short of agreeing to also erase derivatives of the data.