This chapter helps the reader to distinguish experimental research from other quantitative traditions and describes the paradigmatic hierarchy of experimental research. It compares and contrasts experimental laboratory and field experiments and recognizes data analytic techniques aligned to research questions addressed in experimental research. The chapter covers two types of designs: crossover and time series. A crossover design is the major type of within-groups experimental design with many variations depending on the research scenario. Time-series designs are considered quasi-experimental; however, rather than with the other quasi-experimental designs, as they also share characteristics with within-groups designs, such as examining the same participants over time. The chapter outlines major threats to external and internal validity, as well as methods for addressing these potential limitations to increase the rigor of one's experimental study.