Posted on: 2nd Apr 2020 3353 Views

# Reliability and validity of research

Reliability and validity are two terms that the investigator uses interchangeably. Students associated with the research field have confused between reliability and validity. Our professional team is providing an overview of reliability and validity in this article.

## Overview of reliability and validity

Both terms reliability and validity researcher generally utilizes interchangeably. Reliability refers to the level of consistency.

For instance, if any action is taken five times then the result should be the same. A test is considered to be as valid if it measures the thing which is expected. Valid tests are also considered to be as reliable.

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## What is reliability?

Reliability can be referred to as consistency in test scores.

For example, a thermometer is a reliable tool that helps in measuring the accurate temperature of the body. In a similar way, math tests can be helpful in testing the mathematical skills and knowledge of students. You can utilize a number of tools for measuring reliability. Some of the tools for measuring reliability are:

• Kuder- Richardson: It is a tool which researcher mainly utilize for measuring internal reliability.
• Cronbach’s  Alpha: It measures internal reliability for tests with multiple possible answers.

### Internal and external reliability

Internal reliability also is known as internal consistency which will help you in measuring how effective your test is in measuring what it expects to be. External reliability can refer to measures that can be generalized. External reliability refers to the test which can be generalized beyond what you are utilizing it for.

Parallel reliability is reliability where two corresponding tests are provided to students for a short period.  If forms are parallel then you can expect that test will produce similar outcomes.

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### Reliability coefficient

The reliability coefficient can be referred to as the effectiveness of measures in the testing measurement of achievement. It can be considered to be a combination of different coefficients. The number of tests which you can perform for computation of coefficient is:

• Cronbach’s alpha: it is a type of test that most researchers generally utilize for measuring the internal consistency coefficient.
• Simple correlation: This is one of the best techniques for determining the reliability coefficient. In such types of tests, you need to measure scores at different times.
• Pearson correlation: The researcher generally performs such type of investigation for estimating the theoretical reliability coefficient between correspondent tests.
• Spearman-Brown formula: you can use such a test for measuring reliability for split-half tests.
• Cohen’s Kappa: Investigator utilizes such types of tests for measuring inters- rater reliability.

Note: The range of reliability varies from o to1. The preferred level of correlation is the Rule of Thumb.

## What is validity?

Validity refers to tests that researchers mainly design for accurately measuring things.

For example:  if someone perceives that the length of the index finger represents the self–esteem. In case you try to measure self-esteem by measuring the length of your finger using a ruler. Such types of measures could have high test reliability and internal consistency.

The 4 different types of validity in research are:

1. Face validity: Extent up to which you can measure the construct of interest by analyzing the face of an individual.
2. Content validity: It is a degree up to which measures cover the construct of interest.
3. Criterion validity: Extent up to which measures of test correlate with other distinct variables.
4. Discriminant validity: It refers to a level up to which the score of the test is not related to the measures of variables that are distinct.

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## Conclusion

Research should be reliable and valid. They serve as the backbone of an argument or conclusion because, if it’s not considered to have a high level of reliability then people will likely discard your conclusions without giving them much consideration.