Personally Identifiable Information (PII)

Information that, on its own or when combined with other data, can be used to identify a specific individual in the real world.

PII is divided into two categories: linked information and linkable information.

Linked information is any data point that can directly identify an individual on its own. Examples include, but are not limited to:

• Full name
• Home address
• Email address
• Social security number
• Passport number
• Driver's licence number
• Credit card numbers
• Date of birth
• Telephone number
• Internet protocol (IP) address

Linkable information, by contrast, cannot identify a person in isolation — but when combined with one or more other pieces of data, it can be used to identify, trace, or locate an individual.

PII is predominantly a US term. The European equivalent is personal data, which carries a similar meaning but with some nuanced differences in legal definition and scope — particularly as codified under GDPR.