Cambridge Analytica sought to use Facebook data to predict partisanship for voter targeting, UK investigation confirms

The former CEO of Cambridge Analytica, Alexander Nix who was last month banned from running a company for seven years, after he signed a disqualification undertaking with the UK insolvency service previously told the UK parliament that CA/SCL had acquired the bulk of the data it was using to build psychographic profiles of voters from major commercial data brokers such as Acxiom, Experian and Infogroup.

The ICO was satisfied that the Facebook data transferred to CA/SCL by Dr Kogans company was incorporated into a pre-existing larger database it already held containing voter file, demographic and consumer data for US individuals.

The data points collected by GSR survey users and their Facebook friends was specifically selected to enable a matching process against pre-existing SCL databases, it writes, explaining its understanding of how CA/SCL used the improperly obtained Facebook data. Matching took place using file sharing platforms and by reference to name, date of birth and location with SCLs existing datafiles being enriched and supplemented by GSRs data about those same individuals and this matched information being passed back into SCL systems.

This resulted for example information including scores for voting frequency, whether likely republican or democrat, voting consistency, and a profile which predicted personality traits matched to information such as voter ID, name, address, age, and other commercial data.

30 million individuals) was then further analysed using machine learning algorithms to create additional predicted scores relating to partisanship and other criteria which were then applied to all the individuals in the database.

These scores were used to identify clusters of similar individuals who could be potentially targeted with advertising relating to political campaigns.

The letter also reveals that a number of unnamed senior figures associated with the scandal have continued to refuse to cooperate with the ICOs investigation.