Difference Between Reliability and Validity

Reliability vs validity

Reliability and validity seem to be synonymous, but they do not mean the same thing. They are actually different things, different terms when they are explained in a technical manner. These terms are often used on scholastic outputs such as thesis studies, term papers, research papers, and the likes. So to avoid confusion, here are the differences of the two.

Reliability is when your measurement is consistent. It means if you are using a certain kind of instrument for a test and the results on the subjects you are testing is the same for the first and second try, then it is considered reliable.

There are two ways in estimating whether a certain thing is reliable or not. The first way is the test or retest and the other is the internal consistency. The test and retest is quite easy. You simply test an idea twice, test 1 and test 2. It must be measured twice in different times, then compare the similarities of the results of the two tests. Then, if the results of the two tests are the same, it means that certain measurement is reliable.

The next way in estimating reliability is internal consistency. This can be done by questioning. Make different sets of question that can measure the same factor. Let this be answered by different people or different groups. And even if different people answered these different questions, but still came out with the right thought, then it must be reliable.

This is the definition of reliability. Now to differentiate it with validity, it is best to define validity as well. In this way, the confusion between the two terms may be fixed. With this it will be easier to distinguish the two from each other.

If reliability is more on consistency, validity is more on how strong the outcomes of the hypothesis are. It answers the question ‘are we right?’ This means if there is a social experiment on a class concerning discipline and then after the experiment the class became more disciplined, then the strength of the conclusion is very strong. This means the validity too is strong.

Validity is categorized into four types, the conclusion, internal validity, construct validity, and external validity. The conclusion validity is focused more on the relationship between the outcome and the program. Internal validity is more on asking what kind of relationship is there between the outcome and the program. Construct validity analyzes how strong the outcome is. External validity is focused more on the general concept of the outcome.

These are some of the differences between reliability and validity.

SUMMARY:

1.

Reliability is more on the consistency of a measurement, while validity is focused more on how strong the outcome of the program was.
2.

Reliability is easier to determine, because validity has more analysis just to know how valid a thing is.
3.

Reliability is determined by tests and internal consistency, while validity has four types, which are the conclusion, internal validity, construct validity, and external validity.

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