Numbering Systems for Genealogy Family Trees
by Vicki Ruthe Hahn
(SGS) Stateline Genealogy Sorter
May 31, 2017
Numbering systems were used more in the past for keeping track of generations in family trees. This was the only way to keep generations of families straight on hand-written forms, family pedigree charts, and for recording in books. Once software tracking became possible, most of the numbering, sorting, and tracking of people became more automated.
People new to genealogy have not had to know how to do any of the various numbering methods. There are times that using a numbering system might help.
I do not know much about these methods, and had to look a long time to find any information about how to use them.
I do know that on Legacy software, the RIN numbers, automatically assigned to each person, can change. They are not important for organizing except for the computer to keep track of individuals.
Some of the most popular numbering systems are: Ahnentafel (Sosa-Stradonitz Method), and the Register, NGSQ, Henry, d’Aboville, Meurgey de Tupigny, and de Villiers/Pama Systems.
I have used the Ahnentafel numbering system while filling out pedigree family charts. It is very handy, and makes an easy tracking system, once you understand it. I have even gotten to a second page of the 5 or 6 generation family pedigree charts.
Ahnentafel, also known as the Eytzinger Method, Sosa Method, and Sosa-Stradonitz Method is the numbering of ancestors beginning with a descendant. This system allows one to know an ancestor’s number without looking at the list and allows one to know an ancestor’s relationship based on their number.
The number of a person’s father is the double of their own number, and the number of a person’s mother is the double of their own, plus one. For instance, if the number of Sam White is 10, his father is 20, and his mother is 21.
See more about how to do that and other numbering systems:
Genealogy Numbering Systems (National Institute) – https://familysearch.org/wiki/en/Genealogy_Numbering_Systems_(National_Institute)