The Inbreeding Coefficient (IC) is a mathematical measurement of the closeness of the relationship between two dogs.
The IC is expressed as a percentage.
The higher the percentage is, the more closely related two animals are.
The lower the percentage is, the more distantly related two animals are.
An IC score of 25% would be equivalent to mating a brother with a sister. In most cases that would be considered a bad cross.
An IC score of 12.5% would be equal to mating a grandfather to a grand-daughter. That is sometimes done by knowledgeable dog breeders to
"fix" a good trait. This close a breeding should be done by knowledgeable breeders only and then only rarely.
High or low scores are neither"bad" nor "good". The IC is just one tool among many that a breeder can use to determine the suitability of a
particular cross.
(Linebred dogs might have high scores and still be very good dogs.
Outcrossed dogs might have very low scores and yet still not be good dogs.)