Experimental Design

Experimental design is one of several forms of scientific inquiry employed to identify the cause-and-effect relation between two or more variables and to assess the magnitude of the effect(s) produced. The independent variable is the experiment or treatment applied (e.g. a social policy measure, an educational reform, different incentive amounts and types) and the dependent variable is the condition (e.g. attitude, behavior) presumed to be influenced by the treatment. In the course of the experiment it is necessary to demonstrate the existence of covariation between variables, its nonspuriousness, and to show that the cause occurred before the effect. This sort of inquiry can take the form of an artificial experiment, carried out in a laboratory scenario, or a natural experiment implemented in a real-life context, ...