External Validity in Research- Types & Examples

External Validity in Research- Types & Examples

Any research aims to find outcomes or results that are useful. One of the best ways through which one can determine the usefulness of any study or research is by analyzing how generalized the findings of the research are. This is what we know as external validity

If any research has this kind of generalized findings, they can be applied in real situations and spaces. External validity is a crucial aspect and can only be achieved in qualitative research, which is non-numerical.

Below we will discuss what external validity stands for and its different types. We will also consider various external validity threats and how to counter them. 

What is External Validity?

The term “external validity” refers to how successfully experiment results can be applied to other populations or settings. The majority of scientific studies do not aim to produce results that solely pertain to the few participants of the research. Instead, scientists and researchers seek to be able to use an experiment’s findings with a broader population. In simple words, it means the applicability of the research’s findings and outcomes. 

The more generalized and applicable the results will be to other people, situations, and places, the higher will be its external validity. These results are essential for applying theoretical knowledge to real-life situations. External validity is used in a number of research studies, psychology being an integral one of them. External validity in psychology is necessary for generalizing the findings on a wider scale to understand human behavior.

A good external validity example can be a study that indicates physical exercises can help students in stronger memory power. Here the research only investigated the student population. So, to generalize its results to other people, it is necessary to replicate the research with different populations. If it obtains similar results in other populations, then we can determine its validity.

ALSO READ: Internal And External Validity: Overview, Definition, Differences, And Application

Types of External Validity

There are different types of external validity, and you must understand them in detail to know their exact features. Correctly identifying the type also helps in determining how to further leverage the study and take the factors to take into consideration. Below are the most highlighted types that you must be aware of:

  1. Population Validity

The degree to which the study’s findings could be generalized to a larger population is referred to as population validity. The group of persons about whom a researcher is attempting to draw conclusions is referred to as the “population.” 

A sample, on the other hand, refers to a specific set of people who participated in the research. The study is relevant to a sizable population if the sample’s findings can be generalized to the population. 

The key factors in this type of validity are the chosen population and the degree to which the sample represents the population. The outcomes which emerge from such studies are valid only for populations that have common characteristics.

  1. Ecological Validity

Another type of external validity is ecological validity. This validity determines if the results of any research can be applied in different situations in the real world. Suppose any study or research has a high ecological validity; they can be used in practice. 

However, studies with low ecological validity will fail in different contexts and situations. They can be applied only in the specific conditions which prevailed during the research or experiment. 

  1. Temporal Validity

As the name implies, this validity type is related to time. Just like the population size and varied situations, time is also an important factor in determining external validity. This type of external validity explains how the findings or the results change over a period of time. 

Temporal validity specifically pertains to how effectively the research findings can be extrapolated to a different time period. High temporal validity indicates that variables will continue to be significant in the future and that research findings can be used appropriately in different contexts.

Popular Threats to The Methodology

External validity in research is exposed to many threats and challenges. Hence, for more accurate and applicable research, it is important to correctly identify them. In this section, we will spot some of the major external validity threats and learn how to tackle them effectively:

  1. Selection Bias

One of the most common threats to external validity is selection biases. Knowingly or unknowingly, biases can come in a study, especially when you are selecting a group of people for your research. It is possible that the sample you choose may not represent the whole population you want to focus on. 

You can select random people or volunteers for the research to reduce this possibility. Consider extending your subject pool to make your research more representative.

  1. Observer Bias/ Experimenter Bias

Another type of bias that may occur unintentionally is the observer’s or the researcher’s bias. Their perspective can possibly affect the outcomes of the study. However, they can be reduced by using various techniques like blind data analysis, standardization, independent validation, etc.

  1. History

Temporal validity often revolves around historical factors. Significant incidents in history, like war or natural disasters, also have an impact on it. Each individual may have additional personal historical influences. For instance, they might experience disease or lose someone in their family. 

These factors may have an impact on how someone behaves during the investigation, which could distort the findings of the study. Selecting an identical set of participants can help overcome historical influences.

  1. Absence of Reality

Low ecological validity can be a result of a lack of reality in the study. If an experiment is conducted in a lab, then the conditions that prevail are controlled and limited. This absence of realism makes such studies’ findings inapplicable to different situations. You can eliminate this threat by conducting experiments in an environment that the individual perceives as most natural. 


External validity is a crucial factor in examining the usefulness or generalization ability of the research’s findings. There are three types of external validity, and all of them have distinct features. In most cases, external validity is subjected to many risks and threats which can be mitigated using suitable techniques. 

Researchers dedicatedly consider the external validity of research to broaden the scope of their study. This is further crucial to make a significant difference in the world and leverage the findings of the study for the greater good. 

Survey Point Team
Experience SurveyPoint for Free
No Credit card required
Try our 14 day free trial and get access to our latest features
blog popup form
Experience SurveyPoint for Free
No Credit card required
Try our 14 day free trial and get access to our latest features
blog popup form