The National Academy of Sciences has released a report entitled "Biometric Recognition: Challenges and Opportunities." The report concluded that biometric recognition technologies are inherently probabilistic and inherently fallible. Sources of uncertainty in biometric systems include variation within persons, sensors, feature extraction and matching algorithms, and data integrity. The report recommends a more comprehensive systems level approach to the contexts, design, and use of biometric technologies as well as peer-reviewed testing and evaluation of the technologies. EPIC has urged the Department of Defense to establish privacy safeguards for the biometric database the US established of Iraqis. See EPIC - Biometric Identifiers and EPIC - Iraqi Biometric Identification System.