Many computer systems can be used in the diagnosis and care of subjects in a clinical study,in dispensing drug supplies,and in performing laboratory tests required by the study protocol.It is important that these systems are closely controlled and perform reliably every time they are used.International regulations require that such systems be well documented.Audits and inspections at clinical study sites under Good Clinical Practice(GCP)will check such systems to be sure that they are reliable in performance and that their data is trustworthy.The Principal Investigator in a study is responsible for the quality of all computer systems used to meet the study protocol and for the quality and trustworthiness of all trial data collected either by paper or computer.