When college admission committees evaluate their candidates, they don’t just focus on the “numbers” (GPA, rank, test scores) but also on the factors that contribute to these numbers. So, when a high school is especially rigorous and/or competitive, admission officials realize that a student in the second decile may, in fact, be stronger than a student in the first decile elsewhere. The admission officials also note if the student has a “rising record” (i.e., grades improved after freshman or sophomore year) or if there were extenuating circumstances that might have affected the grades and thus the class rank (e.g., the student took an exceptionally demanding course load or missed school due to a serious illness or family crisis).
Thus, admission committees don’t look at a rank in isolation, and they realize that at some cut-throat high schools, a single B+ can send a student from the top tenth down to the second one. But, nonetheless, colleges do like to boast that they have high percentages of students who were in the top tenth of their graduating classes. So it’s definitely an advantage to land there, yet it’s not an automatic deal-breaker for those who don’t.
As you probably know, it takes not just great grades and test scores but also some additional pizzazz (unique extracurriculars, exceptional achievements, atypical background, etc.) to get good news from hyper-selective places like Harvard, Stanford, and Duke. So if your overall profile is exceptional and your course selection and grades are strong (despite your second-tenth rank), you should be at least in the running at your target colleges. But if there’s nothing in your application folder than sets you apart from the crowd, then even a top-decile ranking probably won’t get you good news from the most sought-after universities.
Note also that high schools like yours typically send lots of candidates to the colleges you’ve named. So if many of your classmates are applying to Harvard, Stanford, and Duke, those who are ranked above you will have an edge because they, too, attend a competitive high school and yet have managed to land in the first decile. But, even so, your extracurricular passions and accomplishments might still make you a contender, if these outshine those on your classmates’ applications. Although the college folks will tell you that you’re not competing with your classmates, the truth is that the choosiest colleges rarely accept more than a small handful of students from the same high school, so applications to your target universities from first-decile classmates may indeed hurt your odds.
Bottom line: A second-tenth rank won’t bar you from your dream schools for sure, but, since you’re not a recruited athlete, you will need to stand out in some other way to be a serious contender.