ABSTRACT
A brief and practical introduction to some of the crucial concepts and knowledge people are likely to need to be familiar with in order to understand how experiments are designed. The chapter covers issues such as the definition, goals, and features of experimental studies. A significant effort has been made to clarify and provide distinctions among different types of experimental studies that are commonly performed in the domain of learning sciences, and for each type of experiment the potential threats to internal and external validity are elaborated upon.
