What is the difference between reliability and validity? Which is more important?
Reliability refers to the consistency or stability of the test scores; validity refers to the accuracy of the inferences or interpretations you make from the test scores. Both of these characteristics are important. Note also that reliability is a necessary but not sufficient condition for validity (i.e., you can have reliability without validity, but in order to obtain validity you must have reliability). 5.5. What are the definitions of reliability and reliability coefficient? Reliability refers to the consistency or stability of a set of test scores. The reliability coefficient is a correlation coefficient that is used as an index of reliability. Note that there are several different forms of reliability. First is test-retest reliability (the consistency of a group of individuals scores over time). The second type is equivalent-forms reliability (consistency of a group of individuals scores on two equivalent forms of a test). The third type or reliability is internal consistency rel