Validity and reliability are aspects of evaluation that are important when determining how good assessments and tests are. It would be a waste of time to administer exams that are not in alignment with the primary purpose of giving the test in the first place. Furthermore, it is also a total waste of time to administer the same test over and over again if the results do not yield any similarities or if results are not stable or consistent across various groups. The key word here is alignment, so as long as the initial purpose of the test is in alignment with the assessment tool, then one could also be confident that it will elicit accurate results at a much higher degree than if one is not meticulous enough to make sure that all aspects are in alignment. The methods of estimating reliability include test-retest or stability, alternate forms or equivalence, and internal consistency. Test-retest or stability is a method where “the test is given twice and the correlation between the first set of scores and the second set of scores is determined (pg. 341.).” With the alternative forms method, “both forms are administered to a group of students, and the correlation between the two sets of scores is determined. This estimate eliminates the problems of memory and practice involved in test-retest estimates (pg. 343).” Regarding the internal consistency method, which consists of the split-half method and the Kuder-Richardson methods, these methods are utilized “if the test in question is designed to measure a single basic concept, it is reasonable to assume that people who get one item right will be more likely to get other, similar items right…[i]tems ought to be correlated with each other, and the test ought to be internally consistent (pg. 343).” Regardless of the method used, however, the focus of these models are to determine whether or not a test or assessment is stable, constant, and accurate.