A computer system for identifying the most appropriate of the billing categories (Diagnosis Related Groups) prescribed by the a governmental entity as a basis for determining the amount that health care providers, such as hospitals, are to be reimbursed under Medicare and similar programs for services provided to patients. The computer system responds to an initial determination of a category, upon admission of a patient, to list for medical personnel involved in giving care to the patient, such as the attending physician, a few other medically related categories for consideration as diagnosis and treatment proceeds. Only those related categories that can apply to a particular patient are listed for that patient, thereby reducing the time necessary for the physician to review and designate any new category that may be more accurate than the first. When a new category is designated by the attending physician, a new listing is provided the physician with those categories medically related to the newly designated category being listed. A brief review by the physician each day, with a new listing provided by the computer system for the following day's review if the physician designates any change, gives an accurate determination of the most appropriate billing category by the time services to the patient have been completed, such as when a patient leaves a hospital. A billing category determined in a conventional manner by medical records clerical personnel after medical services are ended can then be compared and reconciled with the physician determined category in order to improve the accuracy of the conventional determination.