Standardized testing plays a a formative and summative role in education.
Formative assessments allow teachers and students to better understand how well a student is grasping the content being covered in class so that instruction and learning can be adjusted as needed. Examples of these might be quizzes and unit tests.
Summative assessments provide a data point that (ideally) reflects the student's understanding of the content and material covered in the test. Examples of these might be NC Final Exams or EOCs.