A data processing system is provided for determining clinical outcomes of medical data gathered by the system. The system can allow a person to define a medical study and can then administer the medical study and can collect and analyze data from potentially geographically diverse doctors, patients and other people associated with a study. Users enter sets of medical information. The system can analyze the medical data according to any number of clinical algorithms that may be custom defined and edited before and during the study. The system conditionally outputs the clinical outcome to the user. The clinical outcome 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 physician groups.