WHEN CITING CASES AS AUTHORITY IN A JUDICIAL OPINION, THE WRITER MUST ENSURE THAT CASES ARE CORRECTLY CITED AND THAT THEY STILL ARE VALID LAW. TO CHECK A CITATION USING THE COMPUTERIZED SYSTEM, THE USER TYPES THE CITATION ON A TERMINAL, WHICH TRANSMITS IT TO A CENTRALIZED DATA BASE CONSISTING OF CITATIONS TO ALL FEDERAL CASES. THE USER RECEIVES A SUMMARY OF INFORMATION ON THE CASE (TITLE, YEAR, JURISDICTION, LOCATION IN REPORTING PUBLICATION AND IN PARALLEL REFERENCES, APPEALS, AND SUBSEQUENT CASES THAT AFFECT THE CASE BEING CITED). THE SYSTEM WAS INSTALLED IN THE U.S. COURTHOUSE IN THE DISTRICT OF COLUMBIA IN 1974, AND DATA WERE GATHERED ON USAGE LEVELS, INTEREST IN THE SYSTEM, ACCURACY OF CITATION INFORMATION, AND COST-EFFECTIVENESS. THE SYSTEM PROVED CONSIDERABLY FASTER THAN MANUAL CITATION VERIFICATION, PROVIDED MORE DETAIL ON SUBSEQUENT CASE HISTORIES, AND USUALLY WAS MORE CURRENT. IT TOOK LAW CLERKS APPROXIMATELY 30 SECONDS TO CHECK A CITATION USING THE AUTOMATED SYSTEM, COMPARED TO 2.5 MINUTES PER CITATION FOR MANUAL CHECKS. ALTHOUGH THE VALUE TO THE COURTS OF HAVING MORE ACCURATE CITATIONS AND SAVING CITATION-CHECKING TIME MAY MORE THAN OFFSET THE COST OF THE SYSTEM, THE SYSTEM ITSELF IS NOT COST-EFFECTIVE. THE VALUE OF THE USERS' SAVED TIME DID NOT EQUAL THE COST OF THE SYSTEM. IN ADDITION, THE ERRORS FOUND BY THE SYSTEM WERE RELATIVELY FEW AND COSTLY TO FIND. IT IS NOT RECOMMENDED THAT THE SYSTEM BE ADOPTED BY THE FEDERAL COURTS, ALTHOUGH IT IS RECOGNIZED THAT THE COURTS MAY DECIDE DIFFERENTLY. SUPPORTING DATA ARE INCLUDED. (LKM)