5 Descriptive and Analytical Epidemiological Study Designs (5/5) -- Principles of Epidemiology: A Primer

5 Descriptive and Analytical Epidemiological Study Designs Pedro Rodrigues Curi Hallal and Rafael Miranda Tassitano Descriptive and Analytical Epidemiological Study Designs Overview Public health issues are often complex and involve analyzing the distribution, patterns, mechanisms, and dynamics of health-related states or events within a population. The first step towards better understanding of these issues is to formulate a specific question and then operationalize the answers to it through a scientific process. As an integral component of public health, the core function of epidemiology is to provide evidence-based information on health-related states or events to support decision-making in public health. This chapter will present the key features of common epidemiology study designs, including their main characteristics, strengths, limitations, types of information generated, and applications in public health practice for both descriptive and analytic epidemiology study designs.[1] [2] Learning Objectives By the end of this chapter, you will be able to: - Define the core elements and features used to classify epidemiological study designs. - Differentiate descriptive and analytical epidemiology study designs. - Describe the strengths and limitations of epidemiological study designs. - Discuss the application of epidemiological study designs in public health practice. Epidemiological Study designs Epidemiological study designs can be defined as a set of structured scientific methods and procedures aimed at operationalizing a well-designed research question. In other words, selecting an appropriate study design is a function of the research question. Therefore, researchers/epidemiologists should consider the nature of what (i.e., case definition), who (i.e., people), where (i.e., place), and when (i.e., time) regarding health-related states or events, as well as test hypothesis to answer the why (i.e., cause, risk factors) and how (i.e., mechanism) they occur. Additionally, it is important to note that each epidemiological study design has intrinsic strengths and limitations related to its characteristics, including the processes of selecting, collecting, analyzing, and reporting data. The nature of the epidemiological study designs can be primarily classified as descriptive or analytical based on the purpose of the research question. As we covered in previous chapters, descriptive epidemiology focuses on describing the distribution and patterns of health-related outcomes in terms of people, place, and time, while analytic epidemiology allows for the assessment of hypotheses regarding the associations between exposures and outcomes.[3] Since disparities in the distribution of rates serve to generate hypotheses, descriptive epidemiology designs can also be referred to as hypothesis-generating studies. Before we delve into more details of the common epidemiological study designs, it is important to identify and describe key features of the core c