What does the term reliability mean when used to describe a research instrument?
|
Statistics Definitions > Reliability and Validity Show
Contents:
Overview of Reliability and ValidityOutside of statistical research, reliability and validity are used interchangeably. For research and testing, there are subtle differences. Reliability implies consistency: if you take the ACT five times, you should get roughly the same results every time. A test is valid if it measures what it’s supposed to. Tests that are valid are also reliable. The ACT is valid (and reliable) because it measures what a student learned in high school. However, tests that are reliable aren’t always valid. For example, let’s say your thermometer was a degree off. It would be reliable (giving you the same results each time) but not valid (because the thermometer wasn’t recording the correct temperature). What is Reliability?Reliability is a measure of the stability or consistency of test scores. You can also think of it as the ability for a test or research findings to be repeatable. For example, a medical thermometer is a reliable tool that would measure the correct temperature each time it is used. In the same way, a reliable math test will accurately measure mathematical knowledge for every student who takes it and reliable research findings can be replicated over and over. Of course, it’s not quite as simple as saying you think a test is reliable. There are many statistical tools you can use to measure reliability. For example:
Internal vs. External ReliabilityInternal reliability, or internal consistency, is a measure of how well your test is actually measuring what you want it to measure. External reliability means that your test or measure can be generalized beyond what you’re using it for. For example, a claim that individual tutoring improves test scores should apply to more than one subject (e.g. to English as well as math). A test for depression should be able to detect depression in different age groups, for people in different socio-economic statuses, or introverts. One specific type is parallel forms reliability, where two equivalent tests are given to students a short time apart. If the forms are parallel, then the tests produce the same observed results. The Reliability CoefficientA reliability coefficient is a measure of how well a test measures achievement. It is the proportion of variance in observed scores (i.e. scores on the test) attributable to true scores (the theoretical “real” score that a person would get if a perfect test existed). The term “reliability coefficient” actually refers to several different coefficients: Several methods exist for calculating the coefficient include test-retest, parallel forms and alternate-form:
The range of the reliability coefficient is from 0 to 1. Rule of thumb for preferred levels of the coefficient:
What is Validity? Click on the link to visit the individual pages with examples for each type:
ReferencesEveritt, B. S.;
Skrondal, A. (2010), The Cambridge Dictionary of Statistics, Cambridge University Press. ---------------------------------------------------------------------------
Need help with a homework or test question? With Chegg Study, you can get step-by-step solutions to your questions from an expert in the field. Your first 30 minutes with a Chegg tutor is free! Comments? Need to post a correction? Please Contact Us. What is the definition of reliability in research?Reliability refers to how consistently a method measures something. If the same result can be consistently achieved by using the same methods under the same circumstances, the measurement is considered reliable.
What is reliability in research example?When it comes to data analysis, reliability refers to how easily replicable an outcome is. For example, if you measure a cup of rice three times, and you get the same result each time, that result is reliable. The validity, on the other hand, refers to the measurement's accuracy.
What is reliability and validity of research instrument?The main objective of questionnaire in research is to obtain relevant information in most reliable and valid manner. Thus the accuracy and consistency of survey/questionnaire forms a significant aspect of research methodology which are known as validity and reliability.
Why is reliability of the research instrument important?The purpose of establishing reliability and validity in research is essentially to ensure that data are sound and replicable, and the results are accurate. The evidence of validity and reliability are prerequisites to assure the integrity and quality of a measurement instrument [Kimberlin & Winterstein, 2008].
|
