<p>Yep, this same error in reasoning appears over and over, so often that I have written a FAQ about it (applying specifically to the case of applying to all eight Ivy League colleges, but the principles are more general): </p>
<p>APPLYING TO ALL EIGHT IVIES </p>
<p>Wrong extreme idea 1: </p>
<p>Some students "reason" that if an applicant applies to all eight Ivy League colleges, his chance of admission at any one of them is the same as the average base admission rate for all of them (which is wrong assumption a). Then the students "reason" that because the eight admission committees don't all meet in the same room, that they select students "independently" in the STATISTICAL sense (which is wrong assumption b). The students then misapply a formula learned in high school that only applies to differing situations, to calculate that the chance of getting into some Ivy League college is almost a sure thing. </p>
<p>What's wrong with wrong assumption a is that a weak applicant for admission at the least selective Ivy League college is a weak applicant at all the other colleges in the league, and that means that applicant's chance of admission anywhere is well below the base rate of admission for any Ivy League college. </p>
<p>What's wrong with assumption b is that usually colleges don't have to actively collude to end up choosing similar kinds of applicants. ALL colleges prefer stronger applicants to weaker applicants. A teacher of statistics explained to me what "independence" means in the sense used by statisticians: "What is independence? It means that when you learn about the outcome of one event, it has no influence on your guess about the probability of success in another event. However, in this case, if a student gets rejected from 8 schools, that DOES influence my guess about how likely he is to get rejected from the 9th school. I'd say someone who gets rejected from 8 schools is more likely to get rejected from the 9th than someone who didn't get rejected from 8 schools." In other words, even if colleges act independently in the layman's sense of the term, you can't use the multiplicative rule of probability to figure out the joint probability of being admitted to one out of the eight Ivy League colleges. Plenty of students get rejected by all eight. </p>
<p>Other threads from time to time bring up </p>
<p>Wrong extreme idea 2: </p>
<p>Ivy League admission officers are thin-skinned and personally offended if you apply to their "competitors," and will reject you if you apply to all eight Ivy League colleges. </p>
<p>Well, that's just ridiculous. There are plenty of students each year who are admitted to more than one Ivy League college (of course, those are rather extraordinary students) and there are at least a few each year who apply to all eight and are admitted to all eight. Ivy League colleges do NOT collude in this manner when making admission decisions. They admit the students who they think will fit well into the next entering class and contribute to the campus community. The bottom-tier Ivy League colleges admit a lot of students who don't enroll (that is, those colleges have rather low "yield,") because they admit some students who prefer to enroll at one of the OTHER Ivy college colleges that admitted them. Each college has its own tricks, in five cases including binding early decision programs, to identify students who genuinely prefer that college, but in the regular action round, every college admits some students who are also admitted by some of the other Ivy League colleges, perhaps all of the Ivy League colleges. </p>
<p>Bottom line: don't worry about either wrong, extreme idea. Apply well to all of the colleges that interest you. There is little point in applying to a college you wouldn't possibly attend if admitted, but there is every reason to apply to a college you like, because you can't get in if you don't apply.</p>
<p>Good luck in your applications. Don't use calculations that apply (well, maybe they do) to coin flips or dice tosses to guess what will happen to college applications.</p>