This is really random, and I might not get a definite answer, but...

<p>I saw my ID number on the MIT admissions dashboard, and I randomly pictured this scenario: A student (ID:1111111) gets an acceptance letter when he was actually supposed to be (unfortunately) rejected, and another student (ID: 1111112) gets rejected when due an acceptance, all because the ID # was mistyped or read. That would really suck, and I'm probably a bit crazy to think this would ever happen. But I am curious as to how the ID number is used other than for classifying documents and sorting them and designating them to a particular applicant. When the admissions officers are discussing a particular applicant, do they refer to said applicant by ID number or name? I do recall somewhere an admissions officer saying that we (college applicants) are not numbers. Thanks in advance for an answer to this odd question. I still have no idea as to why I thought that would ever happen...</p>

<p>I believe you are matched in the files by your name, birthdate, and something like geographic origin or school.</p>

<p>…Then what’s the ID number for? The admissions officers will have a fit trying to pronounce my real name, lol.</p>

<p>A compound primary key (like name + DOB + something else) is usually best from a database design point of view. But it can be a hassle to work with, so you often get a simple numeric secondary key, like ID.</p>

<p>Right, it’s just a simple unique numerical key to index applications. </p>

<p>We refer to applicants by names, because we, like they, are humans :)</p>