DISCREPANCIES IN ENROLLMENT DATA THAT EXIST BETWEEN AGENCIES' AND CARRIERS' ACCOUNTING RECORDS ARE SIGNIFICANT BECAUSE ENROLLEES ON A CARRIER'S RECORDS MAY RECEIVE BENEFITS WITHOUT PAYING PREMIUMS. INTERNAL AUDITORS IN THE DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE (DHEW) UNCOVERED 10,000 DISCREPANCIES (13 PERCENT DISCREPANCY RATE) WHEN COMPARING ENROLLMENT RECORDS OF BLUE CROSS/BLUE SHIELD AND DHEW'S PAYROLL OFFICE. REASONS FOR THESE DISCREPANCIES INCLUDE FEDERAL AGENCIES' FAILURE TO POST CHANGES AND AN OUTDATED MANUAL SYSTEM FOR EXCHANGING INFORMATION BETWEEN AGENCIES AND CARRIERS. BECAUSE DISCREPANCIES ULTIMATELY INCREASE HEALTH INSURANCE COSTS FOR BOTH THE GOVERNMENT AND ITS EMPLOYEES, THE GAO RECOMMENDS THAT THE USE OF AUTOMATED PROCEDURES BE ADOPTED TO REPORT HEALTH BENEFIT ENROLLMENT DATA TO CARRIERS AND TO RECONCILE AGENCY AND CARRIER ENROLLMENT RECORDS. IN ADDITION, THE USE OF A COMMON IDENTIFYING NUMBER FOR EACH ENROLLEE SHOULD BE ARRANGED WITH CARRIERS TO FACILITATE IDENTIFYING ENROLLMENT DATA. CARRIERS SHOULD BE REQUIRED TO PROVIDE PAYROLL OFFICES WITH VERIFICATION ENROLLMENT DATA IN COMPUTER-READABLE FORM, AND AGENCIES AND CARRIERS SHOULD DEVELOP A STANDARD FORMAT FOR EXCHANGING ENROLLMENT INFORMATION.