A data processing system is provided for determining clinical outcomes of medical data gathered by the system. The system can allow a person (e.g. a doctor) to define a medical study and can then administer the medical study and can collect and analyze data in real-time from potentially geographically diverse doctors, patients and other people associated with a study. The system can analyze the medical data in real-time according to any number of clinical algorithms that may be custom defined and edited before and during the study. The clinical algorithms produce clinical outcome data that can be used for treatment of patients participating in the study immediately after the data is input and analyzed. The medical outcomes can indicate such things as performance comparisons, composite outcomes, and risk stratification and assessments for such things as treatments, drugs, illnesses, doctors, patients and physicians groups.