Microdata

Synonyms

Individual data

Definition

A microdata file V with s respondents and t attributes is an s × t matrix where V_ij is the value of attribute j for respondent i. Attributes can be numerical (e.g., age, salary) or categorical (e.g., gender, job).

Key Points

The attributes in a microdata set can be classified in four categories which are not necessarily disjoint [1, 2]:

• 1. Identifiers. These are attributes that unambiguously identify the respondent. Examples are the passport number, social security number, name-surname, etc.

• 2. Quasi-identifiers or key attributes. These are attributes which identify the respondent with some degree of ambiguity. (Nonetheless, a combination of quasi-identifiers may provide unambiguous identification.) Examples are address, gender, age, telephone number, etc.

• 3. Confidential outcome attributes. These are attributes which contain sensitive information on the respondent. Examples are salary, religion, political affiliation, health condition, etc.

• 4. Non-c...