Recital 27a

In order to determine whether a natural person is identifiable, account should be taken of all the means reasonably likely to be used to identify the natural person directly or indirectly. The identifiability of a natural person should be assessed by the controller, considering the actual technical and organisational measures, and applicable prohibitions by law . In light of the interpretation provided in the case‑law of the Court of Justice of the European Union, it is important to provide further clarity on when a natural person should be considered to be identifiable following the application of pseudonymisation to personal data and the transmission to a recipient. The European Data Protection Board should ensure consistency and support controllers and processors by adopting an opinion on pseudonymisation and anonymisation, assessing and specifying the state of the art of available techniques, as well as the technical and organisational measures and criteria to apply pseudonymisation and anonymisation to personal data effectively and by clarifying circumstances whether and when the application of pseudonymisation to personal data may effectively prevent persons other than the controller from identifying the data subject in such a way that, for them, the data subject is not or is no longer identifiable. The opinion should also address the processing to be undertaken and other measures to be applied in order to effectively render personal data anonymous. It is important that the Board carries out a public consultation with relevant stakeholders prior to issuing its opinion. While controllers remain fully responsible to determine and demonstrate whether pseudonymised data do not lead to reidentification of data subjects by persons other than the controller, the opinion should support and provide guidance to controllers regarding the effective application of pseudonymisation to personal data.