Purpose Limitation

Purpose Limitation is a fundamental data protection principle requiring that personal data be collected for specified, explicit, and legitimate purposes and not further processed in a manner incompatible with those purposes. It is a cornerstone of GDPR and creates significant implications for AI development and deployment.

GDPR Foundation: Article 5(1)(b) states that personal data shall be "collected for specified, explicit and legitimate purposes and not further processed in a manner that is incompatible with those purposes."

Components:

• Purpose specification: Purposes must be identified before collection
• Explicitness: Purposes must be clear and unambiguous
• Legitimacy: Purposes must have valid legal basis
• Compatibility: Further processing must be compatible with original purposes

AI Challenges: Purpose limitation creates particular challenges for AI:

• Data collected for one purpose may be repurposed for AI training
• AI model outputs may serve purposes beyond original data collection
• Transfer learning may apply data to unforeseen uses
• Feature discovery may reveal purposes not originally intended

Compatibility Assessment: GDPR Article 6(4) provides criteria for assessing compatible purposes: relationship between purposes, context, nature of data, consequences for data subjects, and appropriate safeguards.

EU AI Act Integration: Article 10(5) allows special processing of sensitive data for bias detection "to the extent that it is strictly necessary" for that purpose—a purpose-limited exception.

Related concepts: Data Minimization, Data Governance, Lawful Basis, Training Data