Summary: The Supplemental Security Income program, which provides cash benefits to the aged, the blind, and the disabled, could be run more efficiently. More importantly, millions of dollars in overpayments could be prevented or detected quickly if information were available on-line during eligibility assessments. GAO estimates that direct on-line access to state computerized income information could have prevented or quickly detected more than $131 million in overpayments caused by unreported or underreported income nationwide in one 12-month period. However, in Social Security Administration (SSA) field offices where direct access to computerized state information has been implemented, SSA claims representatives did not use it to detect overpayments. The claims representatives did use it to process claims more efficiently, and SSA's preliminary results have shown that its use has reduced administrative expenses. Establishing on-line access between SSA field offices and state agency databases would require only minimal computer programming in most states; some states would need additional hardware, such as computer lines.