According to our text, Kubiszyn and Borich, for a test “To be a “good” test, a test ought to have adequate evidence for its validity, reliability, and accuracy for the purpose it is being used for and for the persons with whom it is being used” (Kubiszyn & Borich). A few other factors that affect test score reliability are group variability, scoring reliability, test length, and item difficulty.With group variability, the text explains this concept is affected by the size of a validity coefficient. As group variability increases, score reliability goes up which in turn group variability affects the size of the validity coefficient. (Kubiszyn & Borich)In order for a test to acquire scoring reliability, a test-retest can be used. With a test-restest, the test is given twice, and the correlation between the first set of scores and the second set of scores is determined. (Kubiszyn & Borich, 305) The main problem with test–retest reliability data is that there is usually some memorization involved the second time the test is taken. Which means that the scores maydiffer because the students themselves may have changed in some way. (Kubiszyn & Borich).