One of the foundational EU GDPR principles, set out in Article 5(1)(a), is that personal data must be processed “lawfully, fairly and in a transparent manner in relation to the data subject”. Article 6 sets out concrete circumstances in which processing will be “lawful”, and Articles 12-14 provide further specific requirements for ensuring that processing is “transparent”. But the text of the GDPR—like the Data Protection Directive before it—contains very little additional guidance on when processing will be “fair” i.e., when processing will have “the quality of treating people equally or in a way that is reasonable”, as the Oxford English Dictionary defines fairness.