Screening mammography has been shown to reduce breast cancer mortality by detecting small, nonpalpable, early-stage breast cancers. In 1998, several studies were published, reinforcing the value of screening mammography in women aged 40 years and older. Some studies focused on when screening should begin (age 40 years), while others analyzed the process of screening mammography, with particular attention to recall rates and false-positive studies. Other reports emphasized the limitations of mammographic interpretation, the use of computers to aid in mammographic diagnosis, and screening with ultrasound.