This document provides an overview of research design. It discusses the objectives of research design which are to gain background information, measure variables of interest, and test hypotheses. The three main types of research design are exploratory, descriptive, and causal. Exploratory research is conducted when little is known to develop hypotheses. Descriptive research describes variables through cross-sectional and longitudinal studies. Causal research tests hypotheses through experiments that manipulate independent variables and measure effects on dependent variables.