Purity is produced from Acxiom’s InfoBase File and is compiled from the information derived from product warranties, product registrations, lifestyle questionnaires and magazine subscriptions, in conjunction with other external reference files. Every year 12.6 per cent of UK residents move house, creating 5.5 million changes of address. Purity is a suppression file that eliminates individuals known to be no longer living at an address with 98.1 per cent accuracy. It is a list of 17 million non-residents, i.e. people who are known for definite not to live at an address anymore, because someone else at that address has more recently responded via a survey or a warranty card.

This file is complied from over 20 years experience of collecting and processing accurate targeted data. It has been proven that 30% of gone-aways recorded by postal returns are false, therefore Purity has deliberately excluded any postal returns to prevent over suppression, and is based purely upon validated non-residents.