E-Verify is a system to electronically verify work eligibility and operated by the Department of Homeland Security's (DHS) U.S. Citizenship and Immigration Services (USCIS) and the Social Security Administration (SSA). GAO testified in June 2008 that ensuring accuracy and combating fraud were challenges facing E-Verify. As requested, GAO examined the extent to which USCIS and SSA took efforts to (1) reduce tentative nonconfirmations (TNC) and E-Verify's vulnerability to fraud, (2) safeguard employee personal information, and (3) prepare for possible mandatory use by all employers nationwide. GAO reviewed key policy and procedural documents, interviewed relevant DHS and SSA officials, and conducted site visits to three states selected, in part, based on employer types. GAO recommends, among other things, that USCIS disseminate information to employees on the importance of consistently recording their names, DHS components develop procedures to help employees correct inaccurate personal information, USCIS develop reliable cost estimates for E-Verify, and SSA assess risks associated with its E-Verify workload costs.