Internal Validity (IV): The extent to which we can say that the effect is actually caused by the manipulation. The key point is to take good control of manipulation implementation & Extraneous Variable. Field experiment is inevitably bad for IV but good for External Validity (EV)–the extent to which the effect found can be replicated or generalized to the real world settings.
Continue reading “Internal/External Validity: the Control of Independent, Dependent, and Extraneous Variables in Laboratory or Field Experiments.”