What is Epidemiology?

Epidemiology is the study of determinants of health in a well-defined population. It is the study of the distribution and pattern of “health-related states or event,” which include the outbreak of disease, the distribution of vaccinations, the living conditions or habits of a group, and the availability of health care and health education. The study of these patterns helps public health professionals draw important conclusions about the needs of the population in question.

Epidemiology is often called the cornerstone of modern public health research and practice because the method of surveilling a population, collecting data, and determining trends is characteristic of modern public health’s blending of scientific analysis and social observation. Epidemiology relies on a number of other public health areas, including biology, biostatistics, social sciences, and exposure assessment (assessing the risk of exposure to a threat).


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Epidemiology prepares MPH students to design studies, collect and analyze statistical data, and interpret and disseminate results. Clinical research and the study of biological factors of public health have benefited in recent years from epidemiological advancements. Epidemiology informs public policy, and the evidence from epidemiological investigations is important to the development of new medicines, methods of treatment, and coordination of outreach and education.

According to the Association of Schools of Public Health (ASPH), epidemiology is “the study of patterns of disease and injury in human populations and the application of this study to the control of health problems.” The specific competencies incorporated by this discipline require MPH students to be able to:

  • “Identify key sources of data for epidemiologic purposes.”
  • “Identify the principles and limitations of public health screening programs.”
  • “Describe a public health problem in terms of magnitude, person, time and place.”
  • “Explain the importance of epidemiology for informing scientific, ethical, economic and political discussion of health issues.”
  • “Comprehend basic ethical and legal principles pertaining to the collection, maintenance, use and dissemination of epidemiologic data.”
  • “Apply the basic terminology and definitions of epidemiology.”
  • “Calculate basic epidemiology measures.”
  • “Communicate epidemiologic information to lay and professional audiences.”
  • “Draw appropriate inferences from epidemiologic data.”
  • “Evaluate the strengths and limitations of epidemiologic reports.”

A concentration or background in epidemiology will prepare you for a numerous different careers. Essentially, any public health-related organization that conducts research into the factors of a society that determine its health needs people who are well-versed in epidemiology. This includes government organizations, pharmaceutical companies, non-profits, global health initiatives, and many others. According to the Bureau of Labor Statistics’ Occupational Outlook Handbook, the job outlook for epidemiologists is expected to rise by 24% between 2010 and 2020. For more specific information on careers, visit our Public Health Jobs page.