ABSTRACT
This chapter focuses on the various methods and procedures employed in research on individual and group differences. Research on human behavior can be and is conducted almost anywhere, in the home, school, clinic, place of business, the street, or wherever people congregate and interact. The internal validity of field research is not invariably lower than that of laboratory-based investigations. To reduce the ambiguity of certain constructs and make psychological theories and research more publicly communicable and interpretable, behaviorally oriented psychologists in particular have emphasized the importance of defining constructs operationally. In explanatory research, a distinction is made among independent variables, dependent variables, and extraneous variables. Selection or construction of a psychometric instrument for a particular research purpose requires a clear description and definition of the individual difference variables to be measured. Planned observations, interviews, and surveys may be used in either prospective or retrospective research studies.
