Introduction to Psychology 10th Edition by Rod Plotnik,Haig Kouyoumdjian

Exercise 12

For a test to be useful, it must have two characteristics. First, a test must measure what it is supposed to measure; this is called (a) _____. Second, a person's score on a test at one point in time should be similar to the score obtained by the same person on a similar test at a later point in time; this is called (b) _____.