Posted on: 2nd Apr 2020 1998 Views

Internal Validity in Research

The extent to which a study shows a reliable cause-and-effect relationship between a treatment and an outcome is known as internal validity. Internal validity in research also denotes the ability of a study to rule out alternate causes for a result.

However, there are always ways for professional scholars like those from Ireland’s Assignment Help company who help offer detailed explanations on what these types of studies entail!

Internal Validity in Research

What is Internal Validity?

Internal validity in research is a level of confidence that the test you have performed for judging the causal relationship between variables is reliable. It is considered to be one of the important measures, particularly in Quantitative research.

An internal validity helps in making sure that the experiment design which the researcher has to choose properly follows the principle of cause and effect.  You must consider internal validity, particularly in scientific and social science research.

Demonstrating trust in the relationship between cause and effect is one of the finest methods to describe internal validity. For example, a physics experiment was done to investigate the effect of heat on metal conductivity, and the results were found to have excellent internal validity.

Almost all potentially misleading variables can be eliminated, and tight controls can be established to isolate other variables.

Internal validity: Examples

Example 1: An investigation performs for analyzing the relationship between income level and the likelihood of smoking has lower internal validity. It has been found from research that there is a relationship between smoking and low-income group.

For example the different types of variables are profession, ethnicity, education, social status, etc. You can not eliminate such variables from the study. It is internal validity which helps in demonstrating that you have evidence that proves that findings have a significant influence on results.

Example 2: An investigator performs research for analyzing the influence of computer programs specially designed for teaching on traditional classroom teaching techniques. The finding of the study reveals that children who are taught using computer program learn quickly.

Another thing which has been discovered from the research is that due to computerized teaching there has been great improvement in grades of children. However, research that other investigators perform reveals that children who are taught using the computer program feels that they are not gaining attention.

An experiment still represents high internal validity, as study manipulation has influence. But investigations perform for research paper has low construct validity, as the cause is not clearly stated.  A researcher mainly emphasizes attention rather than the benefit of computer programs.

Quick Support from Irish Research Paper Writers. Custom Paper Writing Services from Local Irish Writers

How do you know if your research has internal validity?

Internal validity requires three conditions to be met. To empirically prove causality between an independent variable A (your treatment variable) and a dependent variable B, all three conditions must be met (your response variable).

  • Your treatment and response variables are both changing at the same time.
  • Changes in your response variables occur before your treatment.
  • There are no confounding or extraneous elements that can explain your study’s findings.

Factors That Improve Internal Validity

Blinding: Participants—and sometimes researchers—who are uninformed of the intervention they are getting (for example, by using a placebo in a medicine study) avoid their views and behaviours, and hence the study’s outcome, becomes skewed.

Experimental manipulation: Instead of simply monitoring an association without doing any intervention, manipulating an independent variable in a study (for example, offering smokers a quitting program) (examining the relationship between exercise and smoking behaviour)

Random selection: Choosing participants at random or in a way that they are representative of the population you want to research.

Randomization: is the process of assigning people to treatment and control groups at random, ensuring that there is no systematic bias between the two groups.

Study protocol: Adhering to particular methods for the administration of treatment to avoid any unintended consequences, such as doing things differently with one set of people against another.

How do maintain the internal validity of the study?

You can’t have confidence in experimental design, as there are high chances of error. There are several tools that researchers can utilize for confirming the internal validity of the study and establishing causality.  These tools are:

  • Temporal precedence: It is considered one of the crucial tools which help you in determining the relationship between cause and effect. It is the procedure that includes the establishment of the cause which takes place before effect.
  • Covariation of cause and effect: Covariation of cause and effect is a procedure that mainly includes the establishment of the fact that there is a relationship between different variables. It is the element that helps you in demonstrating that findings of research on the specific topic have some kind of influence that you can measure.

For example:  An investigator has performed an investigation for analyzing the learning capability of Greek students. The findings of study represent that students who were taught using computer programs learn in better manner.

It means that if you utilize the computer outcome it will help you in generating positive outcomes. In case, a computer program is not utilized by the researcher that means there will no outcome.

  • Establishing causality through a procedure of elimination: It is considered to be s one of the best techniques to demonstrate the internal validity of your study. As in the above example, you can give many explanations for proving the relationship between student learning and computer program.

A strong experimental research design can help you in finding the missing variable. Some of the techniques which you can use for eliminating confounding variables are randomization, repeat experiments, and control groups. These tools or techniques you can use for maintaining high validity.

What factors can affect the internal validity of the study?

The 7 factors which can threaten the internal validity of research are:

 Threat Explanation Example
Confounding factorsAn unexpected variable that influences the causal relationship is tested in the study.The company can appoint a new manager during the duration of the research which will help them in improving the job satisfaction level.
MaturationThe change in time has a significant influence on the dependent variable.At the time of the investigation which the researcher has performed, employees have gained more experience and have been able to perform well at the workplace which has led to an increase in job satisfaction levels.
TestingThe pre-test which you perform has a significant influence on the outcomes of the post-tests.You need to make sure that workers maintain consistency in answering Questions during both pre and post-test.
Selection of participantsThere can be substantial differences between participants in experimental research.You can select participants voluntarily and influence them to participate in experiments.
MortalityIn case you perform a longer investigation for writing the research paper, there are high chances that participants will quit in between.

If the experimental treatment is the main cause it can create a threat to the internal validity of the study.

Highly dissatisfied employees will leave the job. It will result in an improvement in the average job satisfaction level.

Unsatisfied workers are not selected for the post-test.

Regression towards meanThe acute score is considered close to the average of the second measurement. Research performs for analyzing the influence of low scores on employees’ satisfaction levels.

Findings of research reveal that workers who got low scores have a low satisfaction level as compared to employees with a high score.

InstrumentationThe modification takes place in such a manner that you measure dependent variables during the study.The questionnaire consists of extra questions that are then compared to one main question that has been utilized for the pre-test.


Contact Our Experienced Writing Team For Quality Writing Support