There is often a tradeoff between internal and external validity, due to the fact that that the requirements of a high internal validity is the creation of a controlled and artificial setting for the research, which then limits the application of the results to the natural and real-life situations (Mitchell & Jolley, 2001). The attainment of a high internal validity of a research requires that the participants in the research are shielded from the extraneous factors that may change the relationship between the dependent and the independent variables. On the other hand, the extraneous factors are fully operational in the real-life situations, limiting the application of the findings of a research done in a setting where the extraneous factors were blocked. Therefore, there must b a trade-off between the internal validity and the external validity, such that internal validity is only high where external validity is low and vice versa (Isaac & Michael, 1971).
2. Is there a benefit in achieving a high level of one type of validity (internal versus external) over the other? Is there a way to design a study or series of studies to have high internal as well as high external validity? What would be the benefit?
There is a benefit of achieving a high level of one type of validity over the other, based on the nature of the research in question. The level of internal validity achieved in the study is low, while the level of external validity attained in the study is high.