From Quora: "Should grades be the only determining factor for college admissions?"

John Linneball's answer to Should grades be the only determining factor for college admissions? - Quora <-- Click here for original Quora answer. 
TL; DR. answer: No. Not at all. There are too many important things that can’t be measured using grades.


Much longer answer:
No. At least in the U.S. , different secondary schools (high schools, boarding schools) have different grading standards. Some schools are well-known for grading students very harshly, and others grade very leniently. Some schools are known for math, science, excellence in the humanities, and their students often win national and international academic awards. At other schools, some in the same city as the outstanding public and private schools, students are practically “honor students” if they don’t shoot anyone. Most schools fall in between those extremes.


While colleges can, and do, adjust grades by school (e.g., they know a 4.0 GPA from prestigious boarding school is probably much harder to earn than at 4.0 from an inner city with a 40% graduation rate), they can’t be adjusted completely accurately.


More importantly, grades don’t tell the whole story. Extracurriculars (sports, clubs, volunteer or paid work), tell admissions committees a LOT about what you’re like, what you’re likely to contribute to the college community, what your goals are, etc. They’re eager NOT to admit people who don’t do anything but study. I’ve heard them called “gunners” as a reference to the U of Texas student who, perched in a campus bell tower, shot people with his hunting rifle.


So if all you have on your application is your grades, the school will imagine that’s all you do, and that you’ll potentially be a “gunner” at their school. While “gunners” rarely actually shoot people, they do tend to burn out, drop out, and possibly cause problems for other students and others in the community.


Alternately, without knowing your extracurriculars, school admissions people can’t know what you do when you’re not in school or studying at home. Are you training service dogs for handicapped people? Great! Working a part-time job to save up money or help pay family expenses? Great! Is the part-time job cooking meth, Breaking Bad-style? Not great. Grades can’t tell you what’s going on there, asking the relevant questions can.


And of course, there are standardized tests like the SAT and ACT. For all their faults, these tests provide a decent basis to compare students’ achievements, regardless of where they went to school, their socioeconomic level, etc. A 1500 score is the same for the kid who went to a fancy boarding school as it for a kid who grew up in the projects. They’re not perfect - kids who take SAT/ACT prep courses or work with tutors (like me!) can learn how to get better scores without necessarily knowing any more of the math and English. Don’t get me wrong; it helps more to learn the actual academics, but generally, quality academic instruction is also easier for students from better high schools and better social environments to obtain. So the prep school kid would probably score higher on the SAT or ACT than the same kid if he grew up in the projects, but it would also mean the kid from the projects would be even more impressive if he got a high test score. Even with all those flaws, the SAT, ACT, and other standardized tests, when combined with grades, recommendations, extracurriculars, essays, are better than not using them.


I also know about 75% of U.S. colleges are now test-optional or simply won’t accept standardized test scores. But 25% is still a significant percentage, and there’s no guarantee a “test optional” school won’t select a student who provided the optional scores instead of a similar student who didn’t provide those scores. A good number of people, given those facts, would assume the non-score-reporting applicants took the test, but didn’t do well.
Essays (e.g. the Common Application questions) also help admissions officers determine who they want, and who they don’t, by giving the officers some insight into the applicants’ ideas about what matters to them, their motivation for attending the college, and writing skill. Grades aren’t a good substitute for the essays.


Finally, recommendations are key at any selective college. Your teachers, coaches, club advisors, and sometimes classmates, will write recommendations that directly address not only your academic qualifications, but your quality as person, ability to work with others, and likelihood to succeed in future endeavors. Think “literally anything a person who knows you can tell others, but a grade transcript can’t.” Those are going to help you get into college.


Anyway, this long list boils down to “There are too many important factors to know about a college applicant, that can’t be measured by a grade transcript, to make grades the ONLY basis for determining college admissions.”


Good luck!