This document discusses nonexperimental research design. It defines nonexperimental research as observing phenomena as they occur naturally without introducing external variables. The main types of nonexperimental design discussed are descriptive design, correlational design, developmental design, and epidemiological design. Descriptive design aims to observe and describe variables, while correlational design examines relationships between variables. Developmental design looks at phenomena over time using cross-sectional or longitudinal approaches. Epidemiological design studies disease distribution and causes through cohort or case-control methods. Advantages of nonexperimental design include real-life applicability while disadvantages relate to lack of control over variables.