A Note on EPD Accuracy
|by David Dodge|
All EPDs are accurate.
That's right all EPDs are accurate. EPDs are calculated using a statistical procedure called BLUP. BLUP stands for Best Linear Unbiased Prediction. Because BLUP estimates are unbiased, they are all accurate. So, if all EPDs are accurate what is this accuracy we always talk about? Calling this measure an accuracy is a misnomer. What EPD accuracy actual measures is precision. The EPD accuracy measures how precise the EPD estimate is.
EPD precisions are a measure of risk. If you are very conservative and risk-adverse, use EPDs with high reliabilities (high accuracies). If you are more progressive and risk-tolerant, EPD reliabilities will be less important in your decisions.
Hopefully breed associations can begin to update their EPD reporting practices. Dropping the misnomer of EPD accuracy and replacing it with EPD reliability (dairy breeders use this word) or EPD precision would be a great change to make EPDs easier to discuss and understand.
For more information on EPD reliabilities see:
How Risk Adverse are You?
You Would be Crazy Not to Test!
Adapting Breeding Practices to Genomic Technologies