Tokenization enabled data linkage to be carried out in a privacy-preserving way. It allows analysts to follow the same patient across different data sources (for example, matching a pharmacy claim to a medical claim to an EHR record) without any party in the process having access to the patient's true identity. Well-implemented tokenization is essential for HIPAA compliance and for building longitudinal patient datasets that are both analytically useful and legally defensible. The consistency and accuracy of the tokenization methodology directly affects match rates and data quality.