# Coefficient of relationship

## Relationship Coefficient

... previously referred to as additive relationship

is a genetic term used to measure the fraction of like
genes

shared by two humans or animals. It suggests how reliable the records of one will be in predicting genetic
matters for the other. Determining the relationship coefficient between any two individuals is a two step process:

First determine the number of generations separating the two individuals, by using the process described in the
*Relationship* property of the Sequential System. The resulting
number is expressed as *n* in
the formula below. Or one may simply count the number of generations between the two individuals - ascending from Person
A to the common ancestor C, and descending back down to Person B. Persons A and B, themselves, are not counted. C is
counted in both the ascent and the descent. The total number of generations between A and B is the generational
*n*.)

Then calculate the actual relationship coefficient by applying the formula (1/2)^{n} - meaning one divided
by two, raised to the *n*th power.

## Inbreeding coefficient

The inbreeding coefficient for an individual is simply calculated as one half of the relationship coefficient between the parents.

### Example

Below screenshot is from the genealogy program Aldfaer. Queen Elizabeth II of Great Britain is selected as Proband and King Harald V of Norway is selected as relative. The left frame shows his 14 element KinCode in the left column, center column shows each element's relationship coefficient in percent (%), and column three shows the name of the Knot indiviual for each element.

KinCode element **46.068** with Knot individual Friedrich of Hesse Cassel has been selected in the drop-list
revealing the two ascent lists that constitute this basic relation in the right frame. It is easy to calculate that eleven
generations separate them in this basic relationship. If this was their only kinship, then the relationship coefficient
percent would be 0.0488 - or, expressed more simply, they would be about 0.05%
related to each other. This figure is arrived at through the following calculation:

*n* = 5 + 6 = 11

(1/2)^{11} = 0.000488 = 0,0488%

In a complex kinship, the total relationship coefficient is calculated as the sum of the individual relationship coefficients calculated for each KinCode element. The bottom line of above screenshot shows that the total relationship coefficient percent between Queen Elizabeth II and King Harald V within the specified scope of seven generations is 5.0781%, which makes them 5.08% related to each other or in other words, 5.08% of their genes are identical.