This chapter discusses research design and methodology. It defines research design as the plan or strategy for conducting a study to answer research questions. A good research design identifies the study population, sampling method, data collection tools, and how variables will be measured and analyzed. It ensures validity, objectivity and accuracy of the study. Key components of research design include determining the study population, sample size and method, data collection tools, and addressing ethical issues. The chapter also discusses how to establish causal relationships between variables and minimize the effects of extraneous variables through randomization, matching, and eliminating confounding variables from the study design.