The Difficulty of Defining Sensitive Data—The Concept of Sensitive Data in the EU Data Protection Framework

Abstract The concept of sensitive data has been a mainstay of data protection for a number of decades. The concept itself is used to denote several categories of data for which processing is deemed to pose a higher risk for data subjects than other forms of data. Such risks are often perceived in terms of an elevated probability of discrimination, or related harms, to vulnerable groups in society. As a result, data protection frameworks have traditionally foreseen a higher burden for the processing of sensitive data than other forms of data. The sui generis protection of sensitive data—stronger than the protection of non-sensitive personal data—can also seemingly be a necessity from a fundamental rights-based perspective, as indicated by human rights jurisprudence. This Article seeks to analyze the continued relevance of sensitive data in both contemporary and potential future contexts. Such an exercise is important for two main reasons. First, the legal regime responsible for the regulation of the use of personal data has evolved considerably since the concept of sensitive data was first used. This has been exemplified by the creation of the EU’s General Data Protection Regulation (GDPR) in Europe. It has introduced a number of requirements relating to sensitive data that are likely to represent added burdens for controllers who want to process personal data. Second, the very nature of personal data is changing. Increases in computing power, more complex algorithms, and the availability of ever more potentially complimentary data online mean that more and more data can be considered of a sensitive nature. This creates various risks going forward, including an inflation effect whereby the concept loses its value, as well as the possibility that data controllers may increasingly seek to circumvent compliance with the requirements placed upon the use of sensitive data. This Article analyzes how such developments are likely to influence the concept of sensitive data and, in particular, its ability to protect vulnerable groups from harm. The authors propose a possible interpretative solution: A hybrid approach where a purpose-based definition acquires a bigger role in deciding whether data is sensitive, combined with a context-based ‘backstop’ based on reasonable foreseeability.