THE SOCIAL SECURITY ADMINISTRATION USES A HIGHLY COMPLEX COMPUTER SYSTEM TO COMPUTE BENEFIT PAYMENTS FOR MORE THAN 4 MILLION NEEDY AGED, BLIND, AND DISABLED PERSONS CURRENTLY ON THE SUPPLEMENTAL SECURITY INCOME PROGRAM. OVER $25 MILLION HAS BEEN ERRONEOUSLY PAID BECAUSE OF WEAKNESSES IN THE SYSTEM'S INTERNAL CONTROLS. TO HELP ENSURE THAN ALL CLAIMS AND POSTELIGIBILITY EVENTS ARE ACCURATELY ENTERED AND CORRECTLY POSTED TO THE SYSTEM'S AUTOMATED DATA BASE, AN AUTOMATED EXCEPTION CONTROL PROCESS WAS DESIGNED. HOWEVER, THE PROCESS DOES NOT ALWAYS WORK, AND INACCURATE BENEFICIARY DATA CAN BE ENTERED AND USED TO COMPUTE BENEFIT PAYMENTS. AN AUTOMATED DATA EXCHANGE BETWEEN THE SUPPLEMENTAL SECURITY INCOME COMPUTER SYSTEM AND THE RETIREMENT, SURVIVORS, AND DISABILITY INSURANCE SYSTEM WAS ALSO DEVELOPED. BECAUSE OF INADEQUATE CONTROLS IN THE AUTOMATED DATA EXCHANGE, ABOUT $20 MILLION IN ERRONEOUS PAYMENTS HAVE OCCURRED. SOME CHANGES THAT COULD IMPROVE CONTROLS INVOLVE CORRECTING DEFICIENT EXCEPTION CONTROLS; IMPROVING THE DOCUMENTATION OF THE SYSTEM'S EXCEPTION CONTROL PROCESS AT FIELD OFFICES; RESTRICTING THE SYSTEM OVERRIDE CAPABILITY TO SUPERVISORY PERSONNEL WITH APPROPRIATE AUTHORITY; REMOVING THE DATA EXCHANGE OVERRIDE CAPABILITY AND THE 'DEFAULT VERIFICATION' PROVISION FROM THE COMPUTER SYSTEM; AND MODIFYING THE RETIREMENT, SURVIVORS, AND DISABILITY INSURANCE COMPUTER SYSTEM TO PROVIDE A COMPLETE PAYMENT HISTORY TO THE SUPPLEMENTAL SECURITY INCOME COMPUTER SYSTEM. THE APPENDIXES CONTAIN A MAP OF THE TELECOMMUNICATIONS NETWORK AND A LIST OF THE FIELD OFFICES VISTED. (AUTHOR ABSTRACT MODIFIED--RCB)