Random testing is performed on an unannounced, unpredictable basis on employees whose identifying information such as Social Security number (SSN) or employee number have been placed in a testing pool from which a scientifically arbitrary selection is made. This selection is computer generated to ensure that it is indeed random and that each person in the workforce population has an equal chance of being selected for testing, regardless of whether that person was recently tested or not. Once an individual is selected for testing, the person is notified and must immediately report for a drug test. Since this type of testing has no advance notice, it serves as a deterrent.