Compare and contrast different epidemiological study designs in order to describe their strengths and weaknesses.
Choosing an appropriate study design is a critical decision that can largely determine whether your study will successfully answer your research question. A quick look at the contents page of a biomedical journal or even at the health news section of a news website is enough to tell you that there are many different ways to conduct epidemiological research.
In this course, you will learn about the main epidemiological study designs, including cross-sectional and ecological studies, case-control and cohort studies, as well as the more complex nested case-control and case-cohort designs. The final module is dedicated to randomised controlled trials, which is often considered the optimal study design, especially in clinical research. You will also develop the skills to identify strengths and limitations of the various study designs. By the end of this course, you will be able to choose the most suitable study design considering the research question, the available time, and resources.
Introduction to Study Designs: Ecological and Cross-Sectional Studies
The range of different study designs can be quite confusing. However, to help you navigate the maze of study designs, we can split them into groups which share common characteristics. In this module, you will be introduced to these common characteristics, and you will learn the main principles of ecological and cross-sectional studies, as well as when it is appropriate to use them. By the end of the module, you will be able to identify and critically consider the advantages and disadvantages of these study designs.
Case Control Studies
This module focuses on case-control studies, which is one of the best known epidemiological study designs. Case-control studies are particularly useful when you don’t have the luxury of waiting for a long follow-up period to conclude. In this module, you will learn the key elements of case-control study design, and you will learn how to estimate the appropriate measure of association when presented with data from a case-control study.
Cohort Studies and Nested Studies
Cohorts were ancient Roman military units, but in modern epidemiology the word “cohort” is used to describe a group with a shared characteristic. In cohort studies, we follow groups of people over time, we collect data on their exposure and outcome, and try to estimate whether there is an association between the group-defining characteristic and the outcome of interest. In this module, you will learn how to design such a study, the kind of problems which may arise and how it compares with case-control studies. You will also learn about nested case-control and case-cohort studies, which allow us to harness the advantages of cohort studies in more efficient ways. By the end of the module, you will be able to choose the best study design in a variety of contexts.
Randomised Controlled Trials
Randomised controlled trials are often seen as the gold standard of epidemiological research, especially in clinical settings, and in this module you will learn why. You will learn the main design features of randomised clinical trials, why they are so important, and the difficulties and limitations in applying these principles in real life. By the end of this module, you will know how to design a randomised clinical trial and how to decide which is the best analytical approach for the data you have obtained.