Digital Advertising Guidance: LIAs under the UK GDPR

Posted on Wednesday 17 March 2021 | IAB UK

Guidance on how to conduct a Legitimate Interests Assessment; a legal requirement if you want to rely on legitimate interests to process personal data

As part of our work to address the ICO’s concerns about ad tech and real-time bidding (RTB), we have worked jointly with IAB Europe to develop this practical guide to carrying out Legitimate Interests Assessments (LIAs) in the context of processing data for digital advertising generally, and for RTB. An LIA is a prerequisite for any processing of personal data on the basis of legitimate interests. This guide is designed to help companies understand their obligations, and how to comply with them in practice. 

Our aim is to provide guidance to help establish both consistency across the industry, and a common standard for what a robust and thorough LIA looks like. 


The guidance covers:

  • What an LIA is, as defined in the UK GDPR, and its purpose

  • When you must carry out an LIA

  • How to go about an LIA, the process you must follow as set out in law, and who is involved

  • Guidance on how to carry out each of the stages of the three-part ‘balancing test’ in the context of typical digital advertising data types and processing activities

If you have any questions about this work, please email [email protected].

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