This report presents the results of a U.S. General Accounting Office (GAO) review of lender and Department of Education controls over the accuracy of lender-submitted quarterly billings under the Federal Family Education Loan Program, also known as the guaranteed student loan program. It reports that both lenders and the Department of Education demonstrate lacking or inadequate controls for ensuring accurate and reliable data. While there is no evidence showing material overbillings, the GAO report does indicate that an operating environment exists with a significant potential for errors. Major problems in lenders' systems and data control environments are reported in the following areas: (1) ineffective controls over the integrity of the software programs and access to data used to prepare quarterly billings; (2) inadequate controls over the validity, accuracy, and completeness of processed data; (3) inadequate documentation to support summary totals reported on quarterly billings; and (4) inadequate or no written policies and procedures for preparing the quarterly billings. Further, both the Department of Education and guaranty agencies do not conduct sufficiently comprehensive on-site reviews or edit checks to determine whether lenders' systems and data generate accurate quarterly billings. Appendices provide the scope and methodology of the report and comments from the Department of Education. (GLR)