Summary: Pursuant to a congressional request, GAO provided information on the student population of the District of Columbia's public schools (DCPS). GAO noted that: (1) there was a sizable discrepancy between DCPS 1994-1995 school year enrollment data and the 1990 census count of DCPS pupils; (2) the two counts could not be reconciled, since they represented different school grades in different years; (3) DCPS erroneously selected the sample population and therefore could not validate or invalidate the official DCPS pupil enrollment of 80,450 as of September 29, 1994; (4) there may have been as many as 5,000 pupils in the DCPS database who were not actually enrolled in DCPS; (5) it is questionable whether each school is updating the pupil database for student additions and deletions in a timely manner; and (6) DCPS needs to document all policies and procedures for maintaining its pupil enrollment database, ensure that each school follows those procedures, require schools to obtain acceptable evidence of pupil residency and enrollment data, establish computer controls to ensure data integrity and security, perform annual student counts to update the database, and perform periodic, statistically valid audits of the pupil enrollment population to determine enrollment data accuracy and weaknesses in DCPS controls and systems.