This document discusses key elements of research design including the purpose of a study, type of investigation, study setting, population, time horizon, and importance of considering research design early. It describes exploratory, descriptive and hypothesis testing purposes. Correlational and causal studies are covered as well as field, lab and contrived settings. Individuals, groups, organizations can be units of analysis. Cross-sectional and longitudinal time horizons are presented. Reliability including stability over time and internal consistency are also summarized.