The U.S. Congressional Office of Technology Assessment (OTA) established a health program in 1975. During the next few years, OTA's health program published a series of reports dealing with different aspects of health technology assessment (HTA) in some depth. The key report in this series concerned the efficacy and safety of health technology, which in many ways played a ground-breaking role. It pointed out the pervasive lack of accessible information on efficacy and safety, despite more-than-adequate methods of assessment. It also pointed to many problems that resulted from this lack, and the limited use of such information in clinical practice and policy making. It promoted synthesis of existing literature as a practical method of assessment. Other key reports developed other aspects of HTA, including cost-effectiveness. These reports are generally considered to have shaped the field of HTA at least into the 1990s. OTA also pioneered the use of HTA in determining what preventive services to cover in public healthcare programs.