Principles of Epidemiology

Epidemiology is considered the basic science of public health, and with good reason.
Epidemiology is: a) a quantitative basic science built on a working knowledge of probability,
statistics, and sound research methods; b) a method of causal reasoning based on developing
and testing hypotheses pertaining to occurrence and prevention of morbidity and mortality; and
c) a tool for public health action to promote and protect the public’s health based on science,
causal reasoning, and a dose of practical common sense (2).
As a public health discipline, epidemiology is instilled with the spirit that epidemiologic
information should be used to promote and protect the public’s health. Hence, epidemiology
involves both science and public health practice. The term applied epidemiology is sometimes
used to describe the application or practice of epidemiology to address public health issues.
Examples of applied epidemiology include the following:
• the monitoring of reports of communicable diseases in the community
• the study of whether a particular dietary component influences your risk of developing
cancer
• evaluation of the effectiveness and impact of a cholesterol awareness program
• analysis of historical trends and current data to project future public health resource
needs