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Top Strategies To Ensure Internal And External Validity In Research

Top Strategies To Ensure Internal And External Validity In Research
John Caius
September 08, 2022

The research results are the ultimate product of a research study. After conducting a thorough study, you compile them and present them in the form of a document. What if, at the end of your research, you get to know that your results are not valid? Validity in research is of utmost importance because it shows that your end conclusion is trustworthy and valid. How do you get to know that the research results are valid? Checking the internal and external validity of the research is the answer to this question.

Internal and external validity are two important concepts in research. They reflect whether the research results are trustworthy or not. However, to ensure a high level of internal and external validity in research, you must know some strategies. As you are new to the world of research, you may not know about those strategies and methods. Therefore, today’s article is about those strategies. So, let’s get started with the article by defining validity in research first.

What Does It Mean By Validity In Research?

The idea of measuring the validity of research was put forth by Kelly. According to his definition, “A research study is valid if it measures what it claims to measure.” It means that the research study does not measure something else but the variables that are part of it. For example, a psychological study to measure the intelligence level of children in the UK should only measure the intelligence level, not the memory.

Based on its measurement, there are two types of validities that a researcher measures before publishing the research. One is internal validity, and the other is external validity. A brief description of both types is as follows:

  • Internal Validity. This type research evaluates a research study’s experimental design and methods. It measures the extent to which the experimental design establishes a trustworthy cause-and-effect relationship between the variables.
  • External validity. External validity assesses the applicability of the research findings to the real world. It evaluates how well your research study applies to the real world, and its results represent the actual scenarios. It is also about the reproducibility of the research results in an environment other than the lab.

Also Read: Research Methods For Dissertation – Difference Between Observational And Experimental Methods

Strategies To Ensure Internal Validity In Research

After reading the information above, you now have a good idea about internal validity. You know that ensuring this validity in research is important. However, still, you do not know how to ensure this in your research study. So, a brief description of the top strategies to do this is as follows:

Manipulation Of The Independent Variable

The first strategy is about the manipulation of the independent variable called treatments. It means that you manipulate one or more levels of independent variables and see their effect on the study sample and compare that effect with samples whose variables are not manipulated.

Elimination Of Extraneous Variables

Sometimes some extraneous factors or variables affect the validity of research findings. The technique of elimination is all about eliminating the extraneous variables from the study and keeping them constant during treatment. For example, restricting the study to a single gender.

Inclusion Of Extraneous Variables

The third way to ensure internal validity in research is by utilising the technique of inclusion. This technique asks you to include the extraneous variables in the study and evaluate their individual effect on the dependent variables of the research. Doing this is a bit difficult for students because it is a hectic job to measure the effect separately. So, taking a masters dissertation help is the way to go in this strategy.


Randomisation is a technique to cancel the effect of extraneous variables in the research study and make it more valid internally. In this technique, the researcher selects the samples randomly. It is called the random selection technique. Another technique, random assignment, is also employed. It means that the researcher randomly places the research participants into the research groups. This way, the element of bias also gets eliminated.

Read More: Types Of Quantitative Research – Difference Between Quasi-Experimental And Experimental Research

Strategies To Ensure External Validity In Research

Ensuring internal validity is not enough to tell that a research study is valid. External validity also holds equal importance. So, along with the internal validity of research, you must also ensure that the research is externally valid, too. How? A brief description of the strategies to do this is as follows:

Replications Of The Research Study

The number first strategy to ensure the external validity in research is by replicating the research study, again and again. It includes replicating the study with different samples and different environment setting each time. When you have conducted many studies, the effect of the independent variable can be best predicted.

Reprocessing Or Calibration

Another way to ensure external validity is by reprocessing or calibrating the research study. It means that where there are anomalies in the data, refine them. Use a statistical method to adjust the problems that can harm the external validity of your research. For example, you encounter a problem of uneven groups for some characteristics of the sample, i.e., age. Now, using the calibration strategy, a statistical method of reweighting can be used to reprocess the groups and make them even.

Try Out Field Experiments

Lastly, the external validity of research can be ensured if you use field experiments rather than doing experiments in a controlled environment, i.e., a lab. The natural setting allows for a better understanding of the study samples and produces results that are applicable to real-world phenomena. So, as a researcher, you must give thought to researching the problem in the field instead of in a lab.

Read More About: Applied & Theoretical Research – Importance and Differences


Conclusively, validity in research is all about measuring how trustworthy and meaningful the research results of the study are. Internal and external validity are two types of research validity that play an important role in this measurement. The former measures the validity of the research design, and the latter discusses the applicability of research findings in a real-life setting. So, read all the strategies mentioned above to ensure these validities.

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