Difference Between Internal and External Validity | Internal vs. External Validity

Internal vs. External Validity

Difference Between Interior and External Quality:- In any research, validity refers to the truth of perspectives that are studied, deduced inferences, and resulting conclusions.

Exterior and internal validity are two parameters that are being used to evaluate the results of a research analysis or procedure.

Internal validity is the extent to which a researcher will be able to make the claim,

that no other variables, except the one he’s studying, caused the result;

whereas external validity is the extent to which results of the research can be generalized,

because of the involvement of more than one variable.

Internal Validity

Most of the studies are based on the relationship between two types of variables:

  • dependent
  • independent variables.

Dependent variables are the ones that are affected by the changes in the independent variables.

If a researcher can state that a particular independent variable triggers the dependent variable,

then this usually means that the research has reached the best point in his research.

And this is what, Internal validity is all about.

Research is valid internally when changes in one variable produce an exact change in the variable under study.

For instance, if we study the relationship between the preparation of exams and exam results,

it would be pretty clear that no other variable (teaching methods, extra educational costs, intelligent levels, and so forth) results in good exam results.

Research must be internally valid before widening it to add further variables and results to the system.

If there is a good chance that there can be other variables that can influence the result, the research has a low Internal Validity.

Good research studies are always designed in a way that tries to minimize the cases,

in which any variables other than one independent variable impact the dependent variable.

Examples of internal validity

  • Instruments Change during the study.
  • Participants Drop out of the study.
  • Protocol’s completion failure.
  • Regression to the mean.
  • Subjects Pre-testing.
  • Changes while experimenting, affecting the dependent variable.

For Further Reading

External Validity

External validity is the generalization of any realization of research.

specifically, it is the extent of generalizing results include any case related to the topic under study.

As the main goal of any study is to make inferences about the way,

things work in real life, based on the results of an analysis.

For instance, we can generalize the results of a study on a sample population rather than as a whole.

Similarly, we can use the results of research done with few students and apply it to a real-world setting.

However, a researcher cannot make these inferences without external validity.

If the External Validity of a study is low, the results of the study are not applicable in real life,

which means that the research study won’t reveal nearly anything about the world, beyond the study.

Researchers use strategies like the sampling model and the proximal similarity model to raise the external validity of their studies.

KeyDifferences between Interior and External Quality

  • Description:

Internal Validity: Internal quality is the extent to which the researcher can make the claim that no other variables besides the one, understudy, caused the result.

Exterior Validity: External validity is the extent to which we can generalize the results of an analysis to real-life cases, in particular.

  • Area:

Internal Validity: Internal Validity is concerned with the relation between dependent and independent variables.

Exterior Validity: External validity is concerned with the generalization of results.