Epidemiologists investigate and study diseases and health issues. They may analyze data and study trends in certain populations as well. Epidemiologists will often work in the public or private sector and typically specialize in one area of epidemiology.
While some epidemiologists conduct more lab-based research, others may work in a clinic or public health office and deal more with policy and public health advocacy. Some epidemiologists take on a supervisory role over clinic, lab, or clerical staff.