Internal vs. External Validity: Key Differences to Know

When conducting scientific research, it is important to consider validity. It is the compliance of the experimental base which was chosen by a research paper author with generally accepted standards. It also makes it possible to achieve impeccable results in a search for a solution to a problem. 

Compliance with the results of experiments and the goal of a study is determined by the degree of validity (or efficacy, in some sources). At the same time, there is internal and external validity. It begins to sound complicated, isn’t it? But don’t worry! In this article, you will find out what are both internal and external validity. Also you will learn all key differences between internal validity and external validity so that you never mix these concepts up again. Stay with our research paper writing service to nail this topic.

So, validity is one of the most important characteristics of high-quality scientific research. Every relevant scientific work means that it is reliable. A validity shows its compliance with academic standards, reasonability, and usefulness. 

Let us explain it with a simple example. When you are writing a research paper, you have academic writing rules or standards, plus some requirements of your professor. When you conduct research itself, you also have specific requirements and standards that allow you to get a useful and meaningful result. 

During any study, there is a need to carry out practical work the results of which are subject to evaluation. The result is always correlated with such a concept as a flawless experiment. If the matches are as high as possible, the degree of efficacy is also considered high.

Also, there is internal and external validity. Below you will find out their definitions.

Internal validity is an indicator that reflects the reliability of a conclusion that was obtained after a series of real experimental studies. This is the main requirement that is put forward to each result of an experiment.

External validity is the reliability of a result of a study compared to the results of experiments that are aimed at full compliance with an “ideal” result.

What about the key characteristics of both internal validity and external validity? Let’s delve deeper into their traits as this will help you realize their importance in research. 

Internal Validity Features

The characteristics of internal validity play a crucial role in scientific research as they enable researchers to establish the extent to which their study can demonstrate a causal relationship between independent and dependent variables.

Key features include:

>> Read more: Difference Between Validity and Reliability

External Validity Features 

Regarding characteristics of external efficacy, these help establish generalizability of research results for other groups, conditions, and situations. External validity refers to the degree to which the results of a study can be generalized outside a specific context of a study.

Some of the key features that help establish external efficacy include:

There is a need to realize that external validity is often a compromise with internal one. Studies that are strictly controlled and have high internal efficacy may be less applicable to real-world settings. While studies that are more environmentally valid may have weaker internal validity. Researchers must balance these factors to achieve both external and internal validity.

It is also important to know that a trade off of internal and external efficacy is one of those factors which can reduce the credibility of every result of a study. There is a need for assessing internal and external validity.

During some studies, researchers may lose some control over the variables that affect the course of their study. Therefore, the risk of a possible complication reduces the internal one. However such research usually has high external efficacy, since existing conditions are closer to real-life situations and everyday problems, and lower in opposed cases.

So, there is a need to control such threats while designing a research study. You also have to ensure that the results are trustworthy and can be generalized without a negative correlation between validity.

>> Read more: What Is the Control in an Experiment?

Here’s a good example that shows a trade-off relationship between these 2 types of validity. 

Thus, a study with a high internal validity but dropping external one may have good accuracy for one group and may not be accurate for other populations and settings.Conversely, a study with high external efficacy but low internal one may have generalizable results but may not accurately attribute effects to any intervention being tested.

What is replication? In simple words, it is used to increase the reliability in research. The essence of replication is that a study is repeated in different situations and subjects. It allows researchers to identify whether the main results of an original study can be applied in other circumstances. That is, it determines how applicable a study is to other settings.

In other words, this is a chance to test your experiment and confirm its reliability. Replication is important because it allows you to identify not only how effective your research is in different situations but also make sure of its practical application. For example, replication is important in medicine and psychology.

Both these concepts are important in research methodology. Here are some key similarities between internal validity and external validity:

Now, let’s find out what are key differences between internal and external validity so that you never feel confused when it comes to these terms. 

Now, check out an internal versus external validity comparison chart to get a clear and visual idea of how they differ, what goals they have and what threats they are prone to.

If we talk about indicators of internal efficacy, then it is subject to many threats. For example, conducting experiments may be hindered by many circumstances that occur around. Also, there are natural transformations in the environment. External validity is also threatened in some ways. For example, imagine a study that examines the effects of a particular medication on reducing depression symptoms. If this study only includes participants who are recruited from a single clinic, the sample may not be representative of people with depression in the wider population.

So, let’s check out some threats to internal and external validity in more detail.

The main threat factors are:

The main factors that affect the indicators of external efficacy include:

External and internal validity are significantly different. Thus, scientists should keep a balance between internal and external validity in research. They need to ensure that their research is well-controlled and accurate, as well as applicable to real situations and extendable to other populations, settings, and time periods. 

Ultimately, the goal of the research is to produce results that are valid and applicable to the real world. So, understanding the difference between external and internal validity and keeping the validity features in mind is paramount for the success of a study.