Every teacher has their own opinion on how to accurately evaluate student work. While one teacher may give a student's literature paper top marks, another may see room for improvement. Teachers are human, which means they have implicit biases in how they think. There's no way to make every teacher evaluate work the same way. That's where standardized tests come into play. While teacher evaluations offer room for personal discretion in measuring student success, standardized tests offer a strictly objective measurement. When colleges/universities review student applications, it's not fair to compare a student's grades/GPA from a low-income public school district to a student's grades/GPA from a college preparatory school that costs more than the college to which they're applying. Standardized tests offer an objective comparison for students across the country.
Standardized tests aren't a good measure of intelligence. They measure only how well a student can study and memorize information pro rata, not how intelligent they are.
[P1] Standardized tests are required in most developed countries. [P2] They are a measurement of student success. [P3] They allow for an objective measurement of student success as well as an objective comparison of students.
Rejecting the premises
[Rejecting P2] Standardized tests are not a good test of intelligence.