dear doctor

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.

Read more: Difference Between Reliability and Validity | Difference Between http://www.differencebetween.net/miscellaneous/difference-between-reliability-and-validity/#ixzz52DU4JkrW

so thanks

I agree with Dr.Mutasem. Regards.

I agree with Dr. Akshaykumari Jhala

I agree with the views of Profs. Nabel and Jhala. Best regards

Just noticed Prof. Mutasem's concise explanation which is equally excellent

Dear Neeran, these two terms are not synonymous and are usually used when speaking about various types of assessment and particularly when you assess the students' achievements with standardized tests. The informal tests that are made by teacher and are not standardized, however it is desirable if these two features are present in the test in some degree. For the validity, especially for the content one, it is very important for the question if the test to be represent of the sample material you have covered before. And these informal tests can be valid, bearing in mind that according to the vocational literature there is not an absolute validity. reliability is harder to achieve in these informal tests. The respected colleagues have already posted a link, so I think you can find a lot of information about these two constructs.

Greetings,

Janusheva

Thanks for all answer Doctors....regards

Dear Neeran

Reliability refers to the repeatability of findings. If the study were to be done a second time, would it yield the same results? If so, the data are reliable. If more than one person is observing behavior or some event, all observers should agree on what is being recorded in order to claim that the data are reliable.

Reliability also applies to individual measures.When people take a vocabulary test two times, their scores on the two occasions should be very similar. If so, the test can then be described as reliable.To be reliable, an inventory measuring self-esteem should give the same result if given twice to the same person within a short period of time. IQ tests should not give different results over time (as intelligence is assumed to be a stable characteristic).

Validity refers to the credibility or believability of the research. Are the findings genuine? Is hand strength a valid measure of intelligence? Almost certainly the answer is "No, it is not." Is score on the SAT a valid predictor of GPA during the first year of college? The answer depends on the amount of research support for such a relationship.

There are two aspects of validity:

Internal validity - the instruments or procedures used in the research measured what they were supposed to measure. Example: As part of a stress experiment, people are shown photos of war atrocities. After the study, they are asked how the pictures made them feel, and they respond that the pictures were very upsetting. In this study, the photos have good internal validity as stress producers.

External validity - the results can be generalized beyond the immediate study. In order to have external validity, the claim that spaced study (studying in several sessions ahead of time) is better than cramming for exams should apply to more than one subject (e.g., to math as well as history). It should also apply to people beyond the sample in the study.

best regards

Validity refers to how well a test measures

Reliability is stable and consistent results

Reliability refers to the repeat-ability of findings while Validity refers to the credibility or believability of the research

What do you know about reliability and validity?

Reliability refers to consistency of a measure, research etc. Whereas validity refers to credibility of a measure, research etc. i.e. the measure / research supposed to measure / generate research outcome that it supposed to measure / research etc.

In social science context especially pertaining to measurement, there are different types / ways to measure reliability & validity. Examples of reliability includes: test-retest reliability, parallel-form reliability, inter-item consistency reliability, split-half reliability etc. Examples of validity includes: content validity, criterion-related validity, construct validity etc.

Generally, differences between reliability vs validity can be depicted through the attached diagram. This diagram is extracted from Internet through the following link:

http://www.npmj.org/article.asp?issn=1117-1936;year=2015;volume=22;issue=4;spage=195;epage=201;aulast=Bolarinwa

Sekaran (2003) wrote:

“Very briefly, reliability tests how consistently a measuring instrument measures whatever concept it is measuring. Validity tests how well an instrument that is developed measures the particular concept it is intended to measure. In other words, validity is concerned with whether we measure the right concept, and reliability with stability and consistency of measurement. Validity and reliability of the measure attest to the scientific rigor that has gone into the research study.”

Reference

Sekaran, U., 2003. Research methods for business: A skill building approach. John Wiley & Sons.

Reliability concerns evidence quality, while validity concerns arguments. Reliability is a matter of the degree to which a piece of evidence conveys reality. So a historical document which is 95% reliable correctly reports the facts 95% of the time. Validity is the property of an argument where, if its premises are true (and we don't know whether or not they are), its conclusion follows logically and inescapably.

Thanks for all answer ....

Reliable is genuine or guaranty and Valid is certified or proper in simple words.

Validity refers to the credibility of the research while Reliability refers to the repeatability of its findings.

Thanks and regards

Validity and reliability