A method and computer system for monitoring and controlling the quality of tests performed upon a database. A statistical quality layer is provided, which for each new test to be executed on the database, provides recommendations as to a confidence level to be applied to the test and to a number of additional data records to be added to the database in order to maintain the total expected number of type-I errors of tests performed upon the database. The method and computer system further provide access control of users to the database.