Systems of Measuring Kinship Degree

Most bilateral kinship systems and some unilineal ones make essential distinctions between relatives on the basis of kinship distance for purposes of assigning group membership, determining inheritance and succession rights, and organizing other important social events and interactions. In many cases these distances are assigned whole numbers known as kinship degrees. While a single self-evident system for assessing these quantities might be desirable, several different measures have been developed. For example, Western kinship degree calculations have varied historically and geographically between the Roman or civil system and the Germanic or canon system, which is currently the standard both in Catholic church regulations and English common law.

Basic Kinship Numbers and Calculations

As many as six separate systems of caluculating kinship degree have been proposed by various jurists, geneticists, and anthropologists. All are ultimately based on simple systems of counting links between relatives with reference to their most recent common ancestor. Circles of kinship are often defined in terms of the ambiguous measure of "cousin range". More precise systems include:

Civil Degree
Canon Degree
Collateral Degree
Murdock's System
Parentalia