External And Construct Validity In Research

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Validity is one of the most important aspects of a research study ( ). Validity establishes how accurate and credible ( ) the findings are and how thorough one's research is and did the study measure what it intended to measure ( ). There are four main types of validity in research: conclusion validity, internal validity, external validity, and construct validity. This paper will compare and contrast the characteristics of external, internal, and construct validity. It will also identify the threats associated with external and construct validity and the impact of such treats in research.
Internal Validity
Internal validity is when a researcher is able to determine a relationship based on the program and results …show more content…

If the sample is not randomized, the threats to the study become much higher. Critics will be able to make statements that the participants not being randomilzed are not a good representation of all people and this study only reflects those people that have the same demographics as those who participated in the study.Trochim and Donnelly (2008) indicate, when a sample has been randomalized, it is important that the participants participate in the study and to keep the dropout rates low. This will increase the validity of the study. Randomizing helps prevent critics from identifying the reason why participants did not participate or why participants dropped from the study. Having a high dropout rate may cause critics to determine that the results were scewed based on why participantsss dropped and who actually completed the …show more content…

If a pre-test occurs in the study the pre-test its self will effect the results and will not be able to be generalized to another population that did not receive the pre-test. Critics could say that the pre-test provided clues to the participants which effected the results, whereas if a pre-test was not given this would not be the case. The results are not going to be generalized to participants who do not receive a pre-test.
The effects of how participants react knowing they are a part of a study may change how participants react, thus causing and external threat to the study results. Another reactive effect may be if the participants receive more than one treatment in the same study. Receiving more than one intervention is taking away the validity that this study can be generalized to a single treatment study.
Providing a random sample and plenty of data to indicate how results can be generalized to different populations, settings, and time will help improve the external validity of a study. Trochim and Donnelly (2008) indicate that doing the research in a variety of places with different people and at different time will also increase the external validity of a study. As in internal validity the research design and methodology used to gather the data will help improve validity of the study.
Construct

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