Record Linkage in the Historical Population Register for Norway

The Historical Population Register (HPR) of Norway aims to cover the country’s population between 1800 and 1964 when the current Central Population Register (CPR) takes over. This may be feasible due to relatively complete church and other vital registers filling the gaps between the decennial censuses—In 1801 and from 1865 these censuses were nominative. Because of legal reasons with respect to privacy, a restricted access database will be constructed for the period ca. 1920 until 1964. We expect, however, that the software we have developed for automating record linkage in the open period until 1920 will also be applicable in the later period. This chapter focuses on the record linkage between the censuses and the church registers for the period 1800 until around 1920. We give special attention to database structure, the identification of individuals and challenges concerning record linkage. The potentially rich Nordic source material will become optimally accessible once the nominal records are linked in order to describe persons, families and places longitudinally with permanent ids for all persons and source entries. This has required the development of new linkage techniques combining both automatic and manual methods, which have already identified more than a million persons in two or more sources. Local databases show that we may expect linkage rates between two-thirds and 90 % for different periods and parts of the country. From an international perspective, there are no comparable open HPRs with the same countrywide coverage built by linking multiple source types. Thus, the national population registry of Norway will become a unique historical source for the last two centuries, to be used in many different multi-disciplinary research projects.