the VA, the IOM, veterans service organizations, and individual veterans. The Department of Defense (DoD) briefed the Committee about its current activities and plans to better track the exposures and health conditions of military personnel. The Committee further documented the current process by developing case studies around exposures and health conditions for which presumptions had been made. The Committee also reviewed general methods by which scientists, as well as government and other organizations, evaluate scientific evidence in order to determine if a specific exposure causes a health condition.

The history of presumptions is a fascinating and complex story. In 1921 Congress empowered the VA Administrator (now Secretary) to establish presumptions of service connection for veterans. Only Congress and VA have the authority to establish presumptions for veterans. Since 1921, nearly 150 health outcomes have been service-connected on a presumptive basis by Congress and VA. This process has evolved over the years. The current process for making presumptions can be traced to the Agent Orange Act of 1991 (Public Law 102-4. 102d Cong., 2d Sess.), an act that established a model for decision making by VA that still stands today. In the 1991 Act, Congress asked VA to contract with an independent organization to review the scientific evidence on Agent Orange. VA turned to the IOM of the National Academy of Sciences to carry out these reviews. Subsequently, VA turned to IOM for issues arising from the 1990 Gulf War. Based on the work of a committee, IOM provides VA with reports that describe the strength of evidence that links agents of concern with specific health conditions. VA uses IOM reports and other information in an internal decision-making process to decide whether a presumption will be made.

The Committee carefully studied the current approach to presumptive disability decision making and examined a number of specific case examples. This assessment led to a number of recommendations to improve the process:

• As the case studies demonstrated, Congress could provide a clearer and more consistent charge on how much evidence is needed to make a presumption. There should be clarity as to whether the finding of an association in one or more studies is sufficient or the evidence should support causation.

• Due to lack of clarity and consistency in congressional language and VA’s charges to the committees, IOM committees have taken somewhat varying approaches since 1991 in reviewing the scientific evidence and in forming their opinions on the possibility that exposures during military service contributed to causing a health condition. Future committees could improve their review and classification of scientific evidence if they were given clear and consistent charges and followed uniform evaluation procedures.