Blog (4th )
Why is reliability important?
What is reliability? (In statistics) Reliability is the consistency of a measure, often used to describe a test. A test is considered to be reliable if the researchers get the same/very similar results repeatedly. It is not possible to calculate reliability exactly, however there are different ways that we could estimate and/or increase the reliability of one test.
Reliability is very important to psychological tests, so does to our general life. Businesses would need to get reliable supplier, would need to ensure the reliability of their products…etc. To attract new consumers and maintain the loyal consumers so their businesses could keep running and growing.
Here is a video talking and explaining why is reliability so import? (To the businesses and their logistics department)
In the video,The heads of Logistics of Tetra Pak, Addidas, M&S stated they really need everything is to reliable and they could not/do not want to afford the cost of something being not reliable.
And to the businesses, reliability is really important because they need to maintain/grow their Reputation, Customer Satisfaction, to reduce the Warranty Costs to the lowest, to meet Customer Requirements that are increasing by time, and to keep a Competitive Advantage. In order to test the reliability of the product many businesses would hire a group of people to analysis it, for example RAL (stands for Reliability Analysis Laboratory). https://www.reliabilityanalysislab.com/homepage.asp
Back to Reliability in psychology/statistics, if your data from the test is not reliable, there is no point to publish it; it means the test must have something wrong, and for sure it cannot generalise to the whole or other populations. Reliability usually linked with Validity, Validity is the extent to which a test measures what it is supposed to measure. For the test to be valid it must be reliable; but reliability does not guarantee validity. All measurement procedures would have some potential errors (random error and/or systematic error), the aim of reliability is to reduce and minimise it. The most common types of reliability are test-retest reliability, inter-rater Reliability parallel-form reliability, and internal consistency reliability. Test-Retest Reliability is used to assess the consistency of a test/measure arcoss time. Inter-Rater Reliability is used to assess the degree to which two or more different raters give consistent estimates of the same test, the scores would then be compared to determine the consistency of the raters estimates. Parallel-Forms Reliability is used to assess the consistency of the results of two different tests created in the same content domain. Internal Consistency Reliability is used to measure the consistency of results across items within a test. http://changingminds.org/explanations/research/design/types_reliability.htm
This is a website explaining different types of reliability in a simple way.
However, at some extent reliability might become not as important as I have mentioned above, considering Freud’s theory about personality, it is not quite reliability and valid(at least to me). He suggested there are three elements of personality–known as the id, the ego and the superego–work together to create complex human behaviors. Basically, Id is the evil side of yourself, Ego is the balance, and superego is the angel side. Whereas I do not think this would applied to me and some people, however this theory has been used a lot from the the 1920s till now. Therefore, there are always some special or different cases.
To explain why there are a lot of different ways to estimate/increase reliability of one test, it is because reliability is really important to a test and researchers would definitely love to get their research to the maximum reliability and validity.
In conclusion, reliability is important. Reliability is one of the most important elements of test quality. It has to do with the consistency, or reproducibility, of an examinee’s performance on the test. It would be representative if the test were reliable.