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Types of Reliability

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❶Reliability is a necessary, but not sufficient, condition for validity.

What is Reliability?

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Test-Retest Reliability
Assessing Reliability

The timing of the test is important; if the duration is to brief then participants may recall information from the first test which could bias the results. Alternatively, if the duration is too long it is feasible that the participants could have changed in some important way which could also bias the results.

This refers to the degree to which different raters give consistent estimates of the same behavior. Inter-rater reliability can be used for interviews. Note, it can also be called inter-observer reliability when referring to observational research.

Here researcher when observe the same behavior independently to avoided bias and compare their data. If the data is similar then it is reliable. In this scenario it would be unlikely they would record aggressive behavior the same and the data would be unreliable. However, if they were to operationalize the behavior category of aggression this would be more objective and make it easier to identify when a specific behavior occurs. Thus researchers could simply count how many times children push each other over a certain duration of time.

Manual for the beck depression inventory The Psychological Corporation. San Antonio , TX. Manual for the Minnesota Multiphasic Personality Inventory. Saul McLeod , published The term reliability in psychological research refers to the consistency of a research study or measuring test.

There are two types of reliability — internal and external reliability. Assessing Reliability Split-half method The split-half method assesses the internal consistency of a test, such as psychometric tests and questionnaires.

Test-retest The test-retest method assesses the external consistency of a test. Don't have time for it all now? No problem, save it as a course and come back to it later. Martyn Shuttleworth K reads. Share this page on your website: This article is a part of the guide: Select from one of the other courses available: Don't miss these related articles:.

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The Research Council of Norway. This method provides a partial solution to many of the problems inherent in the test-retest reliability method. For example, since the two forms of the test are different, carryover effect is less of a problem. Reactivity effects are also partially controlled; although taking the first test may change responses to the second test.

However, it is reasonable to assume that the effect will not be as strong with alternate forms of the test as with two administrations of the same test. This method treats the two halves of a measure as alternate forms. It provides a simple solution to the problem that the parallel-forms method faces: The correlation between these two split halves is used in estimating the reliability of the test.

This halves reliability estimate is then stepped up to the full test length using the Spearman—Brown prediction formula. There are several ways of splitting a test to estimate reliability. For example, a item vocabulary test could be split into two subtests, the first one made up of items 1 through 20 and the second made up of items 21 through However, the responses from the first half may be systematically different from responses in the second half due to an increase in item difficulty and fatigue.

In splitting a test, the two halves would need to be as similar as possible, both in terms of their content and in terms of the probable state of the respondent. The simplest method is to adopt an odd-even split, in which the odd-numbered items form one half of the test and the even-numbered items form the other. This arrangement guarantees that each half will contain an equal number of items from the beginning, middle, and end of the original test.

The most common internal consistency measure is Cronbach's alpha , which is usually interpreted as the mean of all possible split-half coefficients. These measures of reliability differ in their sensitivity to different sources of error and so need not be equal.

Also, reliability is a property of the scores of a measure rather than the measure itself and are thus said to be sample dependent. Reliability estimates from one sample might differ from those of a second sample beyond what might be expected due to sampling variations if the second sample is drawn from a different population because the true variability is different in this second population.

This is true of measures of all types—yardsticks might measure houses well yet have poor reliability when used to measure the lengths of insects. Reliability may be improved by clarity of expression for written assessments , lengthening the measure, [8] and other informal means. However, formal psychometric analysis, called item analysis, is considered the most effective way to increase reliability. This analysis consists of computation of item difficulties and item discrimination indices, the latter index involving computation of correlations between the items and sum of the item scores of the entire test.

From Wikipedia, the free encyclopedia. Redirected from Reliability research methods. For other uses, see Reliability. This article includes a list of references , but its sources remain unclear because it has insufficient inline citations. Please help to improve this article by introducing more precise citations. July Learn how and when to remove this template message. Upper Saddle River, N. Theory of mental tests.

Split-half method

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Reliability refers to whether or not you get the same answer by using an instrument to measure something more than once. In simple terms, research reliability is the degree to which research method produces stable and consistent results. A specific measure is considered to be reliable if its.

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Reliability has to do with the quality of measurement. In its everyday sense, reliability is the "consistency" or "repeatability" of your measures. Before we can define reliability precisely we have to .

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Internal validity dictates how an experimental design is structured and encompasses all of the steps of the scientific research method. Even if your results are great, sloppy and inconsistent design will compromise your integrity in the eyes of the scientific community. Internal validity and reliability are at the core of any experimental design. Research Methods › Reliability. What is Reliability? Saul McLeod, published The term reliability in psychological research refers to the consistency of a research study or measuring test. For example, if a person weighs themselves during the course of a day they would expect to see a similar reading. Scales which measured weight Author: Saul Mcleod.

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You are here: AllPsych > Research Methods > Chapter Test Validity and Reliability Test Validity and Reliability Whenever a test or other measuring device is used as part of the data collection process, the validity and reliability of that test is important. Inter-method reliability assesses the degree to which test scores are consistent when there is a variation in the methods or instruments used. This allows inter-rater reliability to be ruled out. This allows inter-rater reliability to be ruled out.