Friday, March 25, 2016

GENEALOGY | Henry Method of Numbering

The two main starting points of genealogical organization are "Pedigrees", which start with a person, probably living, and working backward, and "Family Groups", which start with an ancestor, commonly the earliest one identifiable, and work forward.

The topic is–what is best practice? The criteria I use are two, simplicity and sortability:

Simplicity. A numbering system should require the fewest keystrokes possible.

Sortability.  A numbering system should be sortable using standard sorting routines, which sort numbers first and then letters. Staff members of the Society of Genealogists in London told me that the Roman numerals are becoming less favored because they are impossible to sort by computer using standard alphanumeric sorting algorithms.

Pedigrees – Ascending Numbering Systems – The Ahnentafel

The Ahnentafel. Ahnentafel is German for "ancestor table". This numbering is also known as the Eytzinger Method or Sosa or Sosa-Stradonitz Method. It allows for the numbering of ancestors beginning with a descendant. It is a simple and sortable system.

The principle is simply that the number of people in each generation doubles. So if we start with ourself, there are 2 parents, 4 grandparents etc. So 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 John Smith is 10, his father is 20, and his mother is 21.

The first 15 numbers, identifying individuals in 4 generations, are as follows:
(First Generation)
1 Subject
(Second Generation)
2 Father
3 Mother
(Third Generation)
4 Father's father
5 Father's mother
6 Mother's father
7 Mother's mother
(Fourth Generation)
8 Father's father's father
9 Father's father's mother
10 Father's mother's father
11 Father's mother's mother
12 Mother's father's father
13 Mother's father's mother
14 Mother's mother's father
15 Mother's mother's mother.

Ahnentafel with generation. To show each person's generation, the ahnentafel numbering may be preceded by the generation number, just an added column in a table. It is unnecessary, but could be useful. It is sortable.
(First Generation)
1-1 (01-001) Subject
(Second Generation)
2-2 (02-002) Father
2-3 (02-003) Mother
(Third Generation)
3-4 (03-004) Father's father
3-5 (03-005) Father's mother
3-6 (03-006) Mother's father
3-7 (03-007) Mother's mother

Family Group Numbering (Descending) – Defects

Existing numbering systems for family groups have problems of simplicity or sortability.

Register System

The Register System was created in 1870 for use in the New England Historic and Genealogical Register published by the New England Historic Genealogical Society, in Boston, Mass. It uses both common numerals (1, 2, 3, 4) and Roman numerals (i, ii, iii, iv). Problem: Roman numerals violate the principle of sortability.

(Generation One)
1 Progenitor
2 i Child
   ii Child (no progeny)
   iii Child (no progeny)
3 iv Child
(Generation Two)
2 Child
   i Grandchild (no progeny)
   ii Grandchild (no progeny)
3 Child
4 i Grandchild
(Generation Three)
4 Grandchild
5   i Great-grandchild
    ii Great-grandchild (no progeny)
6 iii Great-grandchild
7 iv Great-grandchild

NGSQ System

The NGSQ System is named for the National Genealogical Society Quarterly published by the National Genealogical Society in Arlington, Virginia, which uses the method in its articles. It is sometimes called the "Record System" or the "Modified Register System" because it derives from the Register System. The main difference is in the method of numbering for children who are not carried forward into future generations. Problem: It uses Roman numerals and plus signs and therefore violates the rule of sortability.

(Generation One)
1 Progenitor
 + 2 i Child
    3 ii Child (no progeny)
   4 iii Child (no progeny)
 +5 iv Child
(Generation Two)
2 Child
    6 i Grandchild (no progeny)
    7 ii Grandchild (no progeny)
5 Child
 + 8 i Grandchild
(Generation Three)
8 Grandchild
 +  9 i Great-grandchild
    10 ii Great-grandchild (no progeny)
 + 11 iii Great-grandchild
 + 12 iv Great-grandchild

d'Aboville System

The d'Aboville System is a descending numbering method developed by Jacques d'Aboville in 1940 that is very similar to the Henry System, widely used in France. This is the system that Thijs Boissevain used for his extensive Boissevain Family Group with thousands of names. Periods are used to separate the generations.  No changes in numbering are needed for families with more than nine children. Problem: The periods are unnecessary if a system is treated for numbering children beyond nine. It violates the rule of simplicity.
1 Progenitor
1.1 Child
1.1.1 Grandchild Great-grandchild Great-grandchild
1.1.2 Grandchild
1.2 Child
1.2.1 Grandchild Great-grandchild
1.2.2 Grandchild Great-grandchild
1.2.3 Grandchild
... etc. to
1.2.9 Grandchild
1.2.10 Grandchild

Henry System

The Henry System is a descending system created by Reginald Buchanan Henry for a genealogy of the families of the presidents of the United States that he wrote in 1935. It can be organized either by generation or not. The system begins with 1. The oldest child becomes 11, the next child is 12, and so on. The oldest child of 11 is 111, the next 112, and so on. The system allows one to derive an ancestor's relationship based on their number. For example, 621 is the first child of 62, who is the second child of 6, who is the sixth child of his parents. In the Henry System, when there are more than nine children, X is used for the 10th child, A is used for the 11th child, B is used for the 12th child, and so on. In the Modified Henry System, when there are more than nine children, numbers greater than nine are placed in parentheses. Problem: The progression X, A, B and the use of parentheses in the modified system do not sort correctly using standard sorting routines.

Other Systems

The Meurgey de Tupigny System uses Roman numerals for generations. Problem: Violates rule of sortability.

The de Villiers/Pama System gives letters to generations, and then numbers children in birth order. Problem: It violates rule of simplicity: The letters in this case are unnecessary and duplicative.

Suggested Solution

Use the Henry System but start numbering the 10th child A, the 11th B and so forth. This makes it sortable.