ABSTRACT
Field research is conducted to obtain data that are representative of people’s true responses to natural situations; however, compared to laboratory researchers, field researchers have less control over independent, dependent, and extraneous variables and over assignment of research participants to conditions of the independent variable. Field experiments attempt to achieve a balance between naturalism and control by manipulating an independent variable in a natural setting and observing the natural behavior that follows. Natural experiments take advantage of events outside the researchers’ control that, in effect, manipulate an independent variable. In quasi-experiments, the researchers manipulate the independent variable using naturally occurring groups as the experimental and control group. Because participants are not randomly assigned to conditions of the independent variable, the groups used in natural and quasi-experiments are nonequivalent. However, the characteristics of these groups should be as similar as possible prior to manipulation of the independent variable. The chapter reviews interrupted and control time series designs and describes how to implement these designs in ways that control for threats to internal validity. The chapter describes observational research, which can vary along the dimensions of researcher participation and deception. The process of developing a sound coding scheme that is based on theory and is free from biases is described.
