Question

Group variability, scoring reliability, test length, and item difficulty all affect test score reliability. How do each of these variables impact test design and how can you mitigate those impacts.

Answer 1

Group variability, scoring reliability, test length and item difficulty all play a major role in score reliability. Each one of these attributions can help with test designs for test score reliability. They can all help in showing ways to improve tests for score reliability and make them more effective. What makes a good test is the reliability of the test. For example we can test like "Can a student take this test several times and the score be the same?" This is a question we need to ask ourselves when deciding how we should layout our test. Group variability all boils down to helping to determine what a test is supposed to measure. It also helps us recognize if the test is given repeated times what will the outcome be? Will it be the same, similar or very different?

Group variability affects the size of the reliability coefficient. Higher coefficients result from heterogeneous groups than from homogeneous groups. Scoring reliability limits test score reliability. If tests are scored
unreliably, error is introduced that will limit the reliability of the test scores. All other factors being equal, the more items included in a test, the higher the reliability of the scores. Reliability of test scores tends to decrease as tests become too easy or too difficult.

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