When testing the accuracy of a finding or hypothesis, it is essential to test whether or not the hypothesis is correct and applicable to the situation it is concerned with. Thus, two methods of validity are present, both responsible for checking different aspects of a hypothesis. These methods are internal and external validity. Internal validity is rarely ignored, and most statements are tested using it. However, many people tend to neglect external validity.
What is Internal Validity?
Internal validity, according to VeryWellMind, refers to how well a statement or finding can be described as the direct result of the cause-and-effect scenario used in an experiment. When you describe two things as having a cause-and-effect relationship, you need to make sure that the same effect could not have been seen as a result of a different cause. This is known as internal validity. Can the researcher say with confidence that the results of the study are correct? If the answer is yes, the study passes the internal validity test.
What is External Validity?
Yes, a study may prove to be accurate when tested on a sample size of the population. But will the same hypothesis apply to other people in different settings and circumstances? External validity is, simply put, the concept of generalizing the results of a study to people other than those who were part of an observation, or a setting other than the one used in the study, as said by Scribbr. Can the results of the study be applied to the world in general? If the answer to this is yes, then external validity is achieved.
Forms of External Validity:
- Population validity:
This type of validity refers to the extent to which the findings of a study about people can apply to the population in general.
If your sample does not adequately reflect the population in general, then population validity is not reached. - Ecological validity:
This type of external validity is concerned with the extent to which the situations studied reflect or apply to situations and settings that occur every day. If the situation used is not treated like a real-life situation by the test subjects, it is not likely to mirror real-life situations and will hence be ecologically invalid.
How to Improve External Validity:
- According to Conjoint.ly, researchers should use random sampling instead of alternative methods. This is because random sampling is likely to reflect the population better.
- The participants should assume that the events in the study are real, thus creating a natural reaction, not an improvised one.
- Use more than one situations or samples to conduct the study in to make sure the same reaction is provided in all the cases.
- Use a regular setting rather than an office or laboratory setting.
It is necessary to know that a study is correct in all kinds of situations and with all kinds of people, for it to be accurate. Therefore, researchers should place more emphasis on external validity.