Achievement test scores are often used in an educational system to determine the level of instruction for which a student is prepared.
High achievement scores usually indicate a mastery of grade-level material, and the readiness for advanced instruction.
Under No Child Left Behind, achievement tests have taken on an additional role of assessing proficiency of students.
Proficiency is defined as the amount of grade-appropriate knowledge and skills a student has acquired up to the point of testing.
The number and type of test items written is determined by the grade-level content standards.