The need to assess how much students have learned has been fundamental in education for as long as there have been students and teachers. Long before standardized tests of achievement came on the scene, teachers were making such judgements. They based them on information gleaned from familiar sources: direct observation of students' work, class recitations, conversations with the student or other teachers, daily quizzes, and final examinations. All these bits of information entered into the marks the teacher gave. They still do and they should. Since we had all these techniques at our disposal, why then were standardized achievement tests welcomed when they came along? There are several reasons.