The hospitals use a sophisticated patient risk classification system, called AtlasTM, to abstract severity scores based on patient medical records, assign patients to an appropriate illness category and submit the data to PHC4. These categories, measured from the point of admission to the hospital, range from a patient who is not very sick to a patient who is near death. These severity scores allow PHC4 to adjust for patients at greater risk of dying or staying in the hospital for a longer period of time than other patients. The AtlasTM system was developed by MediQual Systems, Inc., now owned by Cardinal Information Corporation, and is based on the examination of numerous Key Clinical Findings such as lab tests, EKG readings, vital signs, patientís medical history, imaging results, pathology, age, sex, and operative/endoscopy findings. PHC4 also adjusts independently for the presence of cancer in the patient population included in this report.