Protein digestibility-corrected amino acid score (PDCAAS) is a method of evaluating the quality of a protein based on both the amino acid requirements of humans and their ability to digest it. In order to list % DV for protein on a Nutrition Facts label, you will need to enter either a protein efficiency ratio (PER) or PDCAAS value. You can obtain PDCAAS from a lab analysis or you can calculate the value. This cheat sheet goes over the steps for calculating the PDCAAS value.