Summary: As a result of welfare reform, the Social Security Administration (SSA) now has a new way to identify ineligible prisoners receiving Supplemental Security Income (SSI) payments. Today, SSA receives information from 210 additional prisons, preventing about $3.6 million in erroneous payments to inmates and identifying about $3.3 million in potentially recoverable overpayments already made. Also, SSA now receives some data on prisoners more frequently and in a format more usable than before, preventing at least $2.7 million in erroneous payments. SSA has also prevented $1.6 million in erroneous overpayments and identified $1.4 million in potentially recoverable overpayments for the Old Age and Survivors Insurance and Disability Insurance programs. It has developed new electronic monitoring and control systems for inmate data and makes these data available to other federal and state agencies for their assistance programs, such as the Food Stamp program, which may help them improve the accuracy of their payments. Arguments that the program's $10 million cost is high are balanced against benefits that are likely to enhance the operation of SSI and other federal programs for years to come.