Standardized tests are often debated for how well they accomplish their goal of egalitarianism. The idea behind standardized tests is that they give everyone a chance, regardless of their situation: score well on the test, prove your aptitude. Standardized tests are supposed to be a general measure of intelligence. And general intelligence should be situation-independent. But still, standardized tests have been shown to correlate with socioeconomic status. The issue, to say the least, is complex. But there's an aspect of standardized testing that's often left out of the debate.
Standardized tests are constructed to test students on what they should know. Take the SAT, the mainstay of college admissions. The mathematics section doesn't expect you to be on an accelerated course. But if you don't have any of the concepts tightly under your belt, the test will certainly identify them. Similarly with the verbal section. It doesn't presuppose which texts you've read. But it does ask you to read texts, under time constraints and without any previous familiarity with subject or author. The SAT paints a clear line on the sidewalk and says, "This is where we expect you to be." And if you fall short of the line, they'll quantify by exactly how much.
But what if you exceed the line? Very few students get a perfect overall score on the SAT. But quite a few get perfect or near-perfect scores in one of the sections. Often it's a tradeoff in quantitative versus qualitative skills; students may excel in math but not reading, or vice versa. The SAT is constructed to figure out whether a student is prepared to begin college. But beyond an aptitude for math problems versus reading comprehension, they don't tell you what a student is prepared to do once she is in college.
Still, this is the best-case scenario—a student doing very well on the test. More likely, if the student is especially good at something, the test won't capture it. You could take for instance almost anything that's not math, reading, or writing; but consider drama. Theatre kids may have been considered weird in high school, but, in retrospect, I hope we can all see that there's a significant kind of talent there. Most of these talents are the kinds of things we wish desperately we could pull off as adults: commanding the attention of an audience, helping unlock the best of one's collaborators, a willingness to do something no matter what others might think of it. Obviously, standardized tests can't capture that sort of thing.
The only thing that standardized tests can measure is whether or not a student falls short. They're designed to poke and prod until a soft spot is found. Once the weakness is exposed, the shortcoming is cataloged and the process continues until another is identified. The best thing a standardized test can say about you is that you don't possess readily identifiable weaknesses. Standardized tests only measure the absence of weakness. They do not measure the presence of strength.
This doesn't seem like the kind of thing education ought to be about. What education should do is take a student's natural gifts and encourage her to use them to their fullest potential. An educated citizen is one who brings her gifts to society's table, not one who has proved her ability to survive the battery with the least whimpering. The important part is not figuring out what students are bad at, but what they're good at. That's also the hard part, too.
The reason that standardized tests cannot measure strength is that they are standardized. Strengths aren't one-size-fits-all. Tolstoy wrote that "Happy families are all alike; every unhappy family is unhappy in its own way." In the case of families, the good is uniform and the bad is heterogeneous. For intelligence, it's the opposite. Weaknesses are all alike. That's why the SAT can measure them consistently and across the board. But each strength is strong in its own way. The only test we've developed that's robust enough to identify strengths is called life, and even it's imperfect.
This is not, however, a definite argument against standardized tests. There is one kind of strength they can measure: how well a student takes standardized tests. That shouldn't be the only kind of strength we're interested in. But it shouldn't be discarded either. The reason that students from disadvantaged backgrounds can benefit from tests like the SAT is that it gives them a rare opportunity to compete on the same field as the more privileged. If they win, we should take that seriously.
This is where the wishy-washy, enigmatic "wholistic" evaluation process in college admissions succeeds. It allows for different kinds of students, who are good at different kinds of things, to be considered on the merit that puts them in the best light. It's not perfect, as shown by recent scandals; it needs checks. But an overly standardized process will lead to an overly standardized demographic of students. Ultimately, the point of standardized tests isn't to create a legion of educated citizens who are good at them. It is to create a legion of educated citizens, some of whom are good at them.