This chapter explores experimental data-gathering techniques as they relate to political science research. The chapter begins with a discussion of causal inferences and an explanation of how experiments manage to isolate causal effects. It then outlines in detail how experiments work and describes key issues that researchers should consider when designing an experiment.
The topics discussed with regards to causal thinking include correlation vs causation and the fundamental problem of causal inference. The experimental method is introduced as a response to these inferential problems, and its key features are defined as planned intervention by the researcher and random assignment. The chapter goes on to discuss the ways in which one can determine a study’s internal and external validity, the factors that must be considered when designing an experimental study, and the type of research design an experimenter can adopt (e.g., single-blind vs double-blind design; between-subjects vs within-subjects design).
The chapter also outlines the core features of different types of experiments, including laboratory experiments, survey experiments, field experiments, naturally-occurring experiments, and quasi-experiments. It concludes with an analysis of the key limitations of experimental research, such as ethical issues related to the experimenter’s manipulation of the research environment, as well as concerns related to deception