Record linkage (RL) operations identify the same objects in different databases using common identifiers or unique combinations of variables. Record linkage of surveys usually links responses of a given respondent from a survey to responses of the same respondent in a different survey, or to administrative data relating to the same respondent. Record linkage therefore refers to combining micro data of the same unit. The unit may be not a person, but an organization, a commercial enterprise or a patent application, but the word ‘record linkage’ is generally considered to be confined to micro data on the same unit. Therefore, record linkage is conceptually different from data fusion, in which data of different units is used to generate synthetic data-sets. ...