record linkage description

Here is a good description of "Record Linkage" from the University of Manitoba website:

Record linkage is simply the integration of information from two independent sources. Records from the two sources that are believed to relate to the same individual are matched in such a way that they may then be treated as a single record for that individual. Records brought together in this way are said to be linked. The principles of record linkage may be applied to any field in which it is necessary to bring together information recorded about persons in different places or at different times.