Introduction

*This image was created using napkin.ai; however, the concept, design direction, and creative vision were conceived by Dr. Knight and Chris Cardenas

There are a lot of different kinds of questions we ask in social research; many of these questions have to do with describing or exploring something, but sometimes, we really want to explain something. Occasionally, we may actually want to find the cause of something, or isolate the effect something has on something else. These kinds of questions are impossible to answer without a specific set of research designs: experiments.

Experimental research plays a central role in the social and behavioral sciences, offering a powerful way to explore cause-and-effect relationships. In this chapter, we examine the fundamental structure of an experiment and the conditions that distinguish true experimental designs from other approaches.

You’ll learn about the defining features of a true experiment, including the presence of independent and dependent variables, pretesting and post-testing, and the use of both experimental and control groups. A key requirement for a study to qualify as a true experiment is the random assignment of participants to different groups, which helps eliminate bias and supports stronger causal claims.

We will also explore how additional variables can influence your study’s outcomes. Understanding these variables is essential for designing strong research and drawing accurate conclusions. This chapter introduces extraneous and confounding variables, which can threaten a study’s validity if not properly controlled, as well as mediating and moderating variables, which help clarify or shape the relationships between other variables and offer deeper insight into how and why certain effects occur.

The chapter also introduces quasi-experimental designs, which resemble true experiments but lack random assignment. These designs are often used in real-world settings where randomization isn’t feasible. You’ll examine various types of quasi-experiments and learn how to evaluate their strengths and limitations.

Finally, we address practical considerations that affect the success of both experimental and quasi-experimental research, including how to recruit participants, manage treatment and control conditions, standardize procedures, and monitor study integrity through manipulation checks and pilot testing. By the end of the chapter, you’ll understand how to critically assess experimental designs and apply key principles to your research planning.

* AI was used to help organize my thoughts and suggest clarifying sentences, but all ideas and final writing are entirely my own.