Accuracy and Associated Possible Change
The following table lists the possible change values associated with each EPD
trait at the various accuracy levels. Possible change is expressed as "+" or "-"
pounds of EPD and can be described as a measure of expected change or potential
deviation between the EPD and the "true" progeny difference. This confidence
range depends on the standard error of prediction for an EPD. For a given
accuracy, about two-thirds of the time an animal should have a "true" progeny
difference within the range of the EPD plus or minus the possible change value.
For example, a sire with an accuracy of .65 and birth weight EPD of +1.0 is
expected to have his "true" progeny value falling within ±.92 pounds for birth
weight EPD (ranging between +0.1 and +1.9) about two-thirds of the time.
With the conservative approach taken with respect to heritabilities in the Angus
evaluation, actual EPD changes of animals within the population are much less
than statistics would indicate.