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Data Linkage and Identity Management – Privacy Protecting Record Linkage (PPRL) 

In October 2022 the CDC Foundation convened a set of stakeholders to discuss Privacy Protecting Record Linkage (PPRL). Nearly forty representatives of leading public health organizations, their industry partners and their Centers for Disease Control and Prevention (CDC) colleagues discussed the potential benefits, barriers and sustainable business models for PPRL implementation. 

Read the full summary of this stakeholder session that HLN prepared for the CDC Foundation for reference by public agencies considering using PPRL in their systems.

PPRL is a strategy that allows records to be linked together without revealing identifying information. With PPRL, records from two different sources are linked by encrypting (“hash-ing”) each person’s identifying information within each record. A third party can then compare the hashed values to see if a pair of records are from the same person, without revealing that person’s identity. One key to securing PPRL is a trusted third party (not the entity sending the data, and not the entity ultimately wanting to match the data) who performs the match of the hashed values to produce the linked, de-identified data set.

Using PPRL, public health can connect data sets that were generated independently, enabling new analysis opportunities. Similar data sets can be combined reliably to identify and remove duplicate events, reducing inflated case counts or immunization rates. PPRL can allow public health data sets to be linked to external data sets, which may provide new, richer analytical potential. This is achieved while preserving the privacy of the original records in a HIPAA-compliant manner. 

PPRL was used by CDC to link COVID-19 case and vaccination data and to improve COVID-19 case counts, with CDC receiving de-identified data (data with hashed identifiers) from various sources, then linking the hashed identifiers together to more complete and de-duplicated yet de-identified records, better tracking the spread and prevention of COVID-19. In addition to its value at the federal level, PPRL also has great potential to help state, tribal, local, and territorial (STLT) agencies.

See HLN’s series of blog posts on DMI.