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Comparing Classical and Item-Response Theory

When a new test is developed, test developers typically begin by creating more items than are needed. Item analysis techniques such as CTT and IRT are then used.

Provide an explanation of advantages and disadvantages of CTT and IRT.

Describe two specific circumstances for which IRT might provide meaningful benefits if applied to the development or implementation of the test that you are proposing for children with behavioral problems using intelligence tests and explain why.

Describe two specific circumstances for which CTT might provide meaningful benefits to your test and explain why.

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On IRT & CTT

Item response theory (IRT) & classical test theory (CTT) are the two popular statistical frameworks used to address measurement problems in the likes of developmental tests, test-score equating and in testing for biased test items (Hambleton & Jones, 1993). CTT predicts outcomes of psychological testing like test difficulty as well as test-taker ability by assuming that a person has a true score that can be obtained if there are no measurement errors. The equation is such: Observed Score (OS) = True Score (TS) + Error (E). As for IRT, it is far more defined due to the fact that the focus is on each item in the test and not on the overall test-level focus like in CTT. In CTT, the probability of a correct response is due to the functions of the following parameters - the person taking the exam (i.e. trait, intelligence, ability) and the item itself (i.e. difficulty). IRT on the other-hand is theoretically laden but provides item-based testing for complex evaluations.

IRT is seen as the more popular of the two concurrently due ...

Solution Summary

The expert compares classical and item-response theory.

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