Posted on: 28th Apr 2020

An overview of External Validity in Research

External validity includes the application of the conclusion to scientific study. Researcher generally has focused on identifying the best strategies for maintaining the high external validity of the research.   Therefore, it is very much important for scholars to first develop an understanding of the factors which influence the external validity of the research. In this article, our professionals are providing complete guidelines related to the external validity of the research.


 External validity of  Research: Definition

External validity is an extent up to which results of a study are applicable in other settings.  In simple words, you can define external validity as the way you can generalize your research Findings. Ecological validity is also a part of external validity. It is basically the extent up to which findings of a particular study are applicable to real-world situations.  Another term related to external validity is transfer ability which is also known as the qualitative research design. It refers to the analysis of way research results you can transfer to circumstances of similar nature or characteristics.

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Example of External validity

A person has created a mindful application that can be used on a computer system or mobile.  The researcher is performing research for analyzing the influence of mindful application on the mood of people. Before executing a study, the researcher has developed a hypothesis by utilizing that mindfulness application. Designing of the hypothesis is based on the assumption that mindfulness application will help in reducing negative mood.  One of the team will utilize an application for a particular time period.  It is very much important for the investigator to ensure the elimination of bias during the selection of samples. During the time of experimentation, the researcher has made his assistant blind.  The researcher has also utilized study protocol which an investigator has utilizes for outlining the different processes of study.

After that researcher has measured the confounding variables with mood like the socio-economic background of participants, age, gender, status, etc. In the context of measuring the external validity and ensuring the involvement of all participants in investigation  an investigator will allow people to utilize specific applications at home besides using it only in the laboratory.   The researcher has clearly defined the population and has made the choice of an appropriate sample which further has helped them in ensuring the high validity of the research.

Importance of external research validity

External validity in research is very much important as it helps in answering research questions. Maintaining high external validity is also very much essential for examining whether research findings can be generalized to other studies.

How to measure the external validity of research?

One best technique that you can utilize for measuring the external validity of the research. Is to analyze whether you can apply the conclusion which you have drawn from particular research in other real-life situations or not. In case your research findings are applicable to real-life situations then it means that your research has high external validity. If you find it difficult to replicate the Conclusion of your research then it indicates low external research validity.

Factors that improve the external validity of research

The different techniques which you can utilize for improving the external validity of research are:

a) Inclusion and exclusion Criterion

You can use both inclusion and exclusion criteria for making sure that the population has been clearly defined. Clearly defining the population is very much important for maintaining the high external validity of the study.

b) Psychological realism

For  maintaining high external validity you need to ensure that participants experience different events of study as a real event. Researcher for ensuring that participants have good experience in research, you need to share a story with them. In other words, you should inform them about the aim of your research.

c) Replications

It is one of the best techniques for improving the external validity of the research. This technique includes executing research repeatedly by making a selection of different participants. You can also undertake study in completely different settings for determining whether you are able to produce the same results or not.  Researchers can also apply the Meta-analysis technique for determining whether the influence of the independent variable is reliable or not.

d) Field experiments

It is a type of experiment that researchers generally performed outside the laboratory.

e) Reprocessing or Calibration

It is basically a utilizing statistical methodology for making the adjustment in the external validity of the study.  For instance, in the case in your study there are uneven groups that have similar characteristics (like age) then the researcher can utilize reweighing.

In addition to the above techniques, conducting the field investigation can be helpful, in relation to improving the external validity of study as it involves observing phenomena or participants in a natural setting.

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Factors that threaten External validity

Few factors which threaten external validity are:

1) Situational factors

Some of the key factors such as time, location, characteristics of the investigator, the number of measures can influence the external validity .

2) Pre and post influence

It refers to circumstances in which pre or post-test is some manner link to influence which is observed by the researcher during the study. In simple words, the relationship between cause and effect disappears without the addition of additional tests.

3) Sample features

It is basically a circumstance in which few features of specific samples are responsible for the influence which further results in limitation in the context of generalizations of the findings.

4) Biasness in selection

It is basically a problem related to differences in the group in study that can have a significant influence on external validity and also on the  results of study.   Few factors such as the willingness of participants to participate in the investigation, demographics of people can create a significant threat to the external validity of the study.


It has been concluded from the above article that maintaining the external validity  is crucial for answering the research question. Another thing which has been found from above is that external validity can be improved by taking appropriate measures.

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Author Bio:

Angela Wong

Hi Guys, Happy to help you in research paper writing. I am post graduate from SUSS and now involved in providing assistance to Singapore students for making research projects during masters and Phd scholars. You can consult me for marketing, management, finance, accounting or any kind of research paper writing query