Compare and contrast the concepts of test reliability and test validity

What will be an ideal response?

Answer: The student has a fair amount of latitude with this question but necessary elements for a good answer would include definitions of each concept and at least one example of types of reliability and validity and some mention of methods to assess them. The main point of similarity is that they are both necessary for a useable test, but that while a test can be reliable without being valid it is impossible for a test to be valid if it is not reliable. Reliability concerns a test’s consistency across time, items and raters and concerns temporal consistency reliability, test-retest reliability, internal consistency reliability, etc. Mention of Cronbach’s alpha as the most widely used indicator of reliability and that a range of .70 to .80 is generally acceptable would be good.

Validity concerns the basic issue of whether or not a test measures what it is designed to test and involves such issues as construct validity, face validity, criterion validity, convergent validity, and divergent validity. Providing an example of how one of these types of validity is tested would be good. For example, comparing the results of the test in question to some external standard or behavior tests criterion validity.