A research design is a plan for answering a research question, a plan for testing the hypothesis. Clinical psychology researchers typically rely on four main types of research designs: observational and correlational, experimental, quasi-experimental, and single-case designs. The design researchers choose depends on the research question and hypothesis, and ultimately, their goal for the research. In this section, we will cover each research design and provide examples. As you’ll see, this section provides more details than other sections. This is because choosing the research design is one of the most important steps in the research process.