ABSTRACT
In certain clinical studies, the researcher may wish to evaluate the progress of patients over a certain time period and observe their responses to therapeutic intervention(s). Patients are monitored from the time they enter the study until some well-defined event. This event is often death, but may include other outcomes such as time to hospitalization, organ failure or rejection, or the next seizure. They could also be positive outcomes such as time to recovery, to discharge from the hospital, return to normal renal function, or cessation of symptoms.
