Epidemiology Methods

Epidemiology aims to study patterns of disease and of the factors affecting these patterns within a well-defined conceptual or philosophical framework. Epidemiological investigations can be grouped into four broad categories: Observational epidemiology, experimental epidemiology, natural experiments, and Theoretical epidemiology. Several types study designs and measures of relationship are used in these investigations. An overview of different types of epidemiological designs is provided in Section 2. Relative Risk, Odds Ratio and Attributable Risk are the three most common measures of association often used in these investigations. These measures are described in Section 3. The emphasis is on observational studies, which forms a bulk of epidemiological investigations. The design and analysis issues concerning the prospective and retrospective studies, the two most prominent types of observational studies are discussed. Finally, the chapter concludes with a discussion of areas needing further research.