Quasi-Identifier
Definition
Quasi-identifiers can make people identifiable by combining multiple pieces of information.
A feature that does not uniquely identify a person alone but can enable re-identification when combined with other data.
Simply explained
Individual pieces of information seem innocuous but together may reveal which person is meant.
Why it matters in practice
The term supports companies in selecting technologies sensibly, anchoring them organizationally, and using them competently.
Example from business
Postal code, date of birth, and gender can jointly make individual persons identifiable.
Limits and pitfalls
- Evaluating quasi-identifiers only individually or ignoring publicly available supplementary data.
Origin & history
The term was coined in data protection research on statistical databases and k-anonymity.
Use in mid-sized companies
- Possible application: Postal code, date of birth, and gender can jointly make individual persons identifiable.
Frequently asked questions
What does quasi-identifier mean?
A feature that does not uniquely identify a person alone but can enable re-identification when combined with other data. What mistakes should be avoided? Evaluating quasi-identifiers only individually or ignoring publicly available supplementary data.
Sources
Source checked on 10.10.2026. Editorial application examples are hypothetical; no evidence of real customer results.
Editorially reviewed on: