The field of social psychology relies on empirical research, which is the systematic investigation of observable phenomena in the world. This chapter discusses the research methods used by social psychologists to investigate social behavior, activity, and events. It considers the objectives that typically underlie empirical research, the nature of the hypotheses that guide research, and the factors that affect the validity of research findings. The chapter focuses on potential sources of harm to participants and provides information on various safeguards, such as risk-benefit analysis and informed consent, to protect participants' rights. It also discusses a variety of research methods—surveys, naturalistic observation, archival research, and laboratory and field experiments. The term archival research denotes the acquisition and analysis of information collected previously by others. Sources of archival data include the Census Bureau and other federal agencies, data archives, and newspapers.