This document presents the testimony of Arnold P. Jones, Senior Associate Director of the United States General Accounting Office, before the Senate Subcommittee on Immigration and Refugee Affairs, on the Immigration Reform and Control Act of 1986. The Act established a legalization program that permits undocumented aliens to become permanent residents. Aliens have until May 4, 1988 to apply for residence; Congress is considering extending the deadline. However, extending the deadline may not encourage these aliens to apply for residency because of the following reasons: (1) no reliable data exist to forecast the number of aliens who will apply; (2) The 1.3 to 1.5 million expected applicants are fewer than the initial forecast of 2 to 3.9 million made by the Immigration and Naturalization Service (INS); (3) awareness of the legalization program is high among Hispanics, according to a study that addressed program awareness; (4) extending the deadline may require appropriating additional funds; (5) the operational problems that exist do not threaten the program's viability; (6) the program has similarities to other countries' legalization programs; and (7) studies by others provide reasons why some aliens have not applied. (BJV)