Clinical trials are used to ascertain whether drugs are safe, effective, and the extent to which they provide benefit to patients. This chapter contains some basic information on how clinical trials are designed and analyzed. 14.1: Understanding Clinical Trial Types (Video) 14.2: Statistical Basics Data are all around us. Researchers collect data on the effectiveness of a medication for lowering cholesterol. Pollsters report on the percentage of Americans who support gun control. Economists report on the average salary of college graduates. There are many other areas where data are collected. In order to be able to understand data and how to summarize it, we need to understand statistics. 14.3: Random Sampling Now that you know that you have to take samples in order to gather data, the next question is how best to gather a sample? There are many ways to take samples. Not all of them will result in a representative sample. Also, just because a sample is large does not mean it is a good sample. 14.4: Clinical Studies Now you know how to collect a sample, next you need to learn how to conduct a study. We will discuss the basics of studies, both observational studies and experiments. 14.5: Types of clinical interventions Interventions can be classified into two broad categories: (1) preventive interventions are those that prevent disease from occurring and thus reduce the incidence (new cases) of disease, and (2) therapeutic interventions are those that treat, mitigate, or postpone the effects of disease, once it is under way, and thus reduce the case fatality rate or reduce the disability or morbidity associated with a disease. Some interventions may have both effects. 14.6: Evolution of new intervention products and sequence of study phases Many intervention products, and especially drugs and vaccines, are likely to originate from basic research in laboratories. Such products must go through a long series of tests, before they can be considered for use in the kinds of field trials that are the focus of this book. Before any human use, a new product will be tested in the laboratory for its activity and toxicity in various in vitro and animal test systems. 14.7: Interpreting Clinical Research Sources: Phases of a Clinical Trial infographic from the Lupus Foundation, https://lupustrials.org/about-trials/phases-of-a-trial/