Internal Validity: Making Your Survey Research More Beneficial  

Internal Validity: Making Your Survey Research More Beneficial  

Did you just conduct a survey? The next thing you’ll onto be is researching and analyzing the survey data. When it comes to research, internal validity can come in quite handy. Considered an essential aspect of understanding research data, it simply refers to your confidence level in your research findings.  

Simply put, it is used to determine the extent of accuracy in your research. If your research has no contradictory factors, your research will be held valid.  

Here is everything you should know about internal validity, along with its importance and some examples.  

Understanding Internal Validity: An Introduction  

Before we get into this, let’s take a look at confounding. In simpler terms, confounding is where various factors interfere with the research’s outcome.  

Conversely, internal validity is all about determining the relationship between the test situation and the research outcome. Remember, a lower confounding rate means higher internal validity.  

If you can eliminate possible outcomes from your research, it will be more valid. Moreover, you can only assume the cause-and-effect relationship if you meet the three following requirements:  

  • The cause and effect change simultaneously.  
  • The cause occurs before the impact.  
  • There is no other reason for what you just concluded.  

The sample collected must always be selected and measured correctly if you want the data to be acceptable.  

RELATED: Internal And External Validity: Overview, Definition, Differences, And Application 

Importance Of Internal Validity  

Any research study needs internal validity to ensure the observed effects of an independent variable are the result of manipulating it and not by other confounding factors. In other words, internal validity ensures that the conclusions drawn from a research study are accurate and unbiased. 

Internal validity is essential in research because it allows researchers to establish causality between variables. If a study lacks internal validity, it becomes difficult to determine whether changes in the dependent variable are due to the manipulation of the independent variable or some other extraneous factor. This, in turn, can compromise the credibility and generalizability of the research findings. 

Here are a few pointers that are crucial for ensuring internal validity in research: 

Control of extraneous variables 

To ensure internal validity, researchers must control or eliminate the influence of any variables that are not being studied but could potentially affect the outcome. By randomizing, matching, or managing statistics, this can be accomplished. 

Experimental design 

A well-designed experiment is essential for ensuring internal validity. This includes choosing an appropriate sample size, using reliable and valid measures, and implementing an appropriate experimental design. 

Random assignment 

Random assignment is a critical component of experimental research. It ensures that participants are randomly assigned to groups, which minimizes individual differences’ influence on the outcome. 

Double-blind design 

A double-blind design can reduce the risk of experimenter bias by ensuring that neither the participants nor the researchers know which group is receiving the treatment. 

Statistical analysis 

Appropriate statistical analysis is crucial for ensuring internal validity. This includes selecting appropriate statistical tests, controlling for confounding variables, and conducting appropriate post hoc analyses. 

RELATED: Data Interpretation: Making Your Survey Data Usable  

Threats To Internal Validation  

To make your research successful, you must identify the threats to internal validity. You can incorporate a number of techniques to ensure that you have eliminated all threats.  

However, here are a few threats you might encounter when conducting research.  

Historical Events  

Certain historical events might change the way people think about something. This can influence the quality of your responses when conducting a survey. For instance, natural disasters or changing leadership can change people’s feelings about specific circumstances.  


Note that research conducted over a prolonged period of time will be more susceptible to maturation. The way of thinking can change over time. This might also cause a significant threat to your research if your experiments go through a biological change, like getting old.  

Experimenter Biases  

This is one of the most common threats to your research findings. Experiment bias is when a researcher acts differently towards a group of people.  

This can either be for or against that group of people. Acting according to your preference can affect your research results and might stop you from analyzing the matter.  

RELATED: The Difference Between Sample Bias And Sampling Error 


The reliability of study findings can be compromised when participants interact and observe each other, potentially leading to the issue of resentful demoralization. This may cause control group members to work less effectively due to resentment toward their group. 


Experiments may involve testing the same subjects repeatedly to obtain more precise information. However, regular testing with the exact measurements can affect the participants’ results.  

As they become familiar with the test or the testing process, participants will likely perform better, potentially significantly impacting the outcomes due to repeated testing. 

Some Examples For Internal Validity  

Here are some examples.  

Random assignment 

This reduces the likelihood of selection bias and ensures that any differences between the experimental and control groups are solely caused by the independent variable(s). 

Control group 

A control group is included to compare the experimental and control groups. The control group receives no treatment or a placebo, which helps to rule out alternative explanations for the results. 

Double-blind procedure 

Neither the researcher nor the participants know who is receiving the treatment and who is in the control group. This helps to eliminate the effects of experimenter bias and demand characteristics. 

RELATED: Using Spearman's Rank Coefficient Technique To Analyze Survey Data 

The Takeaway  

To sum up, it is a crucial component of any research study, particularly in surveys. Maintaining internal validity means ensuring that the study allows for valid causal conclusions to be drawn over the relationship between independent and dependent variables.  

However, various factors such as selection bias, demand characteristics, and experimenter effects can threaten internal validity. Researchers should carefully consider these threats and take appropriate measures to control them to ensure that the results of their surveys are trustworthy and accurate.  

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