How much money is enough? Epidemiologists study population and geographical trends to understand the spread of disease, while Medical Scientists study medications, diseases, medical devices, and other aspects of medicine from a scientific perspective. This is her second book. Clicking in this box will show you programs related to your search from schools that compensate us. You will also need to know about company policy regarding job promotions and to plan accordingly. A Doctor of Chiropractic degree requires many hours of residency and many years of schooling, and the job itself is a lifesaver to many patients experiencing pain.