An extensive revision, this classic text presents the most recent advances in social research design and methodology. The authors thoroughly describe the research process using methods derived from basic principles of scientific inquiry and demonstrate how they apply to the study of human behavior. These applications make it an indispensable resource for all fields of human social research, particularly communication, psychology, public health, and marketing. With a heavy emphasis on reliability and validity, the book considers experimental, quasi-experimental, and survey research designs in light of these qualities. Principles and Methods of Social Research is noted for its: *emphasis on understanding the principles that govern the use of a method to facilitate the researcher's choice of the proper methodological approach; *use of the laboratory experiment as a point of reference for describing and evaluating field experiments, correlational designs, quasi-experiments, and survey designs; and *unique chapter on the ethics of social research including the power a researcher wields and tips on how to use it responsibly. Highlights of the thoroughly expanded and updated edition include: *new chapters on meta-analysis and social cognition methods; * the latest on experimental operations and procedures, such as implicit measures, simulations, and Internet experiments; * expanded coverage of conducting experiments outside of the lab, including conducting experiments on the Web and on applied evaluation research methods, including efficacy and effectiveness research. Intended as a text for upper-level and graduate courses in research methods in social psychology, the social sciences, communications, and public health research. No previous methods courses are required.