Standardized tests are at their best when they are used to measure large-scale learning outcomes fairly and consistently. For example, tests like PISA and TIMSS help compare students’ academic performance across countries, providing useful data for improving education systems. These tests are also reliable because every student answers the same questions under the same conditions.

However, standardized tests can be at their worst when they are used as the only measure of a student’s ability. They may not reflect creativity, critical thinking, or other skills that are hard to test with multiple-choice questions. Some students may also perform poorly due to test anxiety, even if they understand the subject. Therefore, standardized testing should be combined with other forms of assessment, like projects or teacher observations, to give a more complete picture of learning.