Table 1.

Aggregated list of potential patient identifiers in datasets

Identifier (information sources)	Comments
Direct
Name [9-16]
Initials [14]
Address, including full or partial postal code [9-16]
Telephone or fax numbers or contact information [9,11,13,16]
Electronic mail addresses [9]
Unique identifying numbers [9-16]	Generalised HIPPA item 7-10, 18
Vehicle identifiers [9]
Medical device identifiers [9]
Web or internet protocol addresses [9]
Biometric data [9]
Facial photograph or comparable image [9,11,12,14]
Audiotapes [12]
Names of relatives [11]
Dates related to an individual (including date of birth) [9,10,12,16]
Indirect--may present a risk if present in combination with others in the list
Place of treatment or health professional responsible for care [11,16]	Could be inferred from investigator affiliations
Sex [10]
Rare disease or treatment [11]
Sensitive data, such as illicit drug use or "risky behaviour" [16]
Place of birth [11,16]
Socioeconomic data, such as occupation or place of work, income, or education [10,11,13,16]	MRC requirement is for "rare" occupations only
Household and family composition [16]
Anthropometry measures [16]
Multiple pregnancies [16]
Ethnicity [10]
Small denominators--population size of <100 [15]
Very small numerators--event counts of <3 [15]
Year of birth or age (this article)	Age is potentially identifying if the recruitment period is short and is fully described
Verbatim responses or transcripts [16]