ABSTRACT
Experiments are a method for data collection by following a procedure to test or try out what is studied in either a laboratory or a real setting. An experimental study often involves the application of multiple techniques for data collection (e.g., using questionnaire or interview for pretest and posttest, performing observation in the experiment process). Experiments are thus considered a meta-method. This chapter presents three major types of experiments: true experiments, quasi-experiments, and pre-experiments. Each comprises more individual designs. The six steps in true experiments are illustrated with an example of a hypothetical COVID-19 vaccine trial. Factors jeopardizing the internal and external validity of experimental studies are examined. Dos and don'ts in experimental research are also discussed, followed by two case studies of experimental research, one for a true experimental design and the other for a quasi-experimental design.
