Nominations is definitely one of the largest variables.
1. Each congressman is only allowed to have up to 5 cadets that they've nominated and was given an appointment, at the academy at one time. So that is basically 1 appointee per year, with the occasional 2nd one in a particular year.
2. While a person can have a nomination and be on the slate of 10 from a representative or senator, that can put you into a pool potentially of approximately 5000-6000 applicants nationally all with nominations that you have to compete with in the general pool.
3. While those with military parents and such are entitled to a "Presidential" nomination, only 100 of those individuals can be given an appointment using that nomination. It is not uncommon to have 500 applicants with presidential nominations. (Thus, why it's important to seek as many nominations as you can get)
4. And as you rightfully pointed out, your district/state could have a lot of people seeking a nomination, with very few slots available.
5. Some representative prioritize their list of 10. (Their prerogative). With the limitation of how many they can have, if you aren't the #1 on that list, you then have to compete in the general pool of thousands nationally.
6. And many other misc. nominations; some also authorized "X" amount of guaranteed appointments.
Outside of the nomination arena, there's the academics. Initially, you aren't competing nationally, but each school is different. Variables in classes and school profile are very important. How does a 4.0gpa taking 1 AP class a semester compare to a 3.8gpa taking 5 AP classes a year. And, in order to remain fair and balanced, what about the student that goes to a school that doesn't have AP classes? Are/Should they be penalized. Obviously, if a student has AP classes available, but they CHOOSE not to take them, they can be penalized. What about the student who doesn't take any AP classes, but is in the IB program where all of their classes are advanced classes, but more importantly, except for 1-2 electives each semester, their entire schedule is already pre-selected. It's an "International" degree program. Children in Dallas, Cheyenne, New York, London, Tokyo, etc... are basically taking the same classes. Then throw in that some school WEIGHT these advanced IB/AP/Honors type classes to give them more value in GOPA compared to the student who only takes traditional classes. Then there's some schools that don't weight classes at all. A 4.0gpa in traditional classes looks the same as a 4.0gpa in the IB program or all AP classes. Then, there's the home schooled, magnet schools, private schools, prep-schools, etc.... As you can see, there are a lot of variables when trying to determine an applicant's FINAL ACADEMIC SCORE. (Which is a number score that maxes at about 805 points or close to that).
Then there are the variables on leadership, athletics, volunteering, etc... The academy doesn't just look at the activities to check a box and say YES or NO S/He filled a square. They evaluate to determine if the activities appear to be part of the applicant's profile (Meaning something they are really into) or is it something they did to fill a square. 1-2 years in a club, compared to 4-5 years in a club. 6+ years of doing a sport, or 1-2 years only in 11th-12th grades. JUST a member of a club, or a LEADER of the club. In leadership roles, are they associated with their extra curricular activities, or more simply window dressing? Maybe the applicant had financial issues at home and spent most of their free time with a part-time job. Did they have leadership positions there? Maybe with athletics, their school was small and private, and they didn't really offer a lot of varsity type sports. Maybe the individual has to join city leagues or they were in non-traditional athletics such as martial arts, polo, etc...
The biggest variable is that no one here is probably from your home town. We don't know your competition, your school district, what's available, where your fellow student go onto after high school, average SAT/ACT scores, etc.... Many of these things when negative, are not the applicant's fault. Most times, the applicant (Student) doesn't get to pick the school they go to, the curriculum they take, etc... That is why the academy requests a copy of your school's profile. So they can see what colleges/universities the average kid graduating high school goes to. If 95% of your high school's graduating college bound students go to State "U", and only 5% go on to big name, private, or out of state colleges; that speaks much differently than a school where 60% go to State "U" and the other 40% go on to big name, private, or out of state colleges.
There are numerous areas of the application process that you are graded on. I.e. they do not write down your 3.8gpa. Based on many of the things I've posted, they calculate that gpa, how it's weighted, combined with SAT/ACT scores, mixed with class ranking, difficulty of the classes, classes available, classes taken, etc.... and they give you an academic score. They then do the same thing with athletics, leadership, extra-curricular, volunteering, etc.... And they give you calculated scores. It is this final score of all these calculated scores, that they use to determine if you will receive an appointment or not.
Of course, there's also some variables that many people don't want to mention, think about, or admit. The military tries very hard to be representative of the country. That is one reason that EACH Congressional representative is allowed to have up to 5 qualified cadets from their district at the academy at one time. Representatives are based on population. By giving each representative the same amount of slots, you allow an equal diversity, percentage wise, from all 50 states. But gender, ethnic background, race, etc... also plays a factor. In a perfectly merit based only scenario, it is possible to have 1300-1400 applicants receive appointments, who were all men. Or all white. Or at least an overwhelming percentage. So; the academy also looks at under-represented individuals. These aren't always race or gender. Maybe they only have 1 person at the academy from Vermont. They might allow a couple more qualified candidates from vermont in. It could simply be that they haven't had any applications from Vermont for a couple of years. My son's ALO didn't have ANY applicants for this newest class of 2013. Last year she had quite a few. So, the diversity factor also plays into this.
The academy website lists all the minimums for entrance into the academy. It's easy enough to find the most recent entering class's profile as far as Average gpa, sat/act, extra curricular, sports, and other information. Between this information, you can accurately tell how you compare to the current average cadets. That still doesn't mean you'll get in, but it gives you an idea if you have to work harder at improving a certain area. But you might be there with the 3.90gpa; but in your district, there are 2 others with higher gpa's, a little better SAT/ACT, etc... and the rep puts them at #1 on their slate of nominees. And being they ranked them, the academy will take their #1 if they are physically/medically/etc... qualified. And if your rep already has 5 cadets at the academy, and because of other variables; you could possibly not get an appointment even from the general pool. But you simply don't know.
Some of the scoring on an individual is subjective. It's simply the board's decision based on their past experiences with applications. Maybe a lot of what I wrote is vague. Maybe it didn't answer any questions. The only advice I can give anyone is to do their best and make their goal the max. Your goal each semester is to get an "A" in every class. It's to get a 2400 on the SAT and a 36 on the ACT. It's to be the best in all your activities. Then, whether you receive an appointment or not, you can walk away knowing you did your best. And that in return will give you rewards in the other schools you applied to. And for what it's worth, just about every college/university in the country that has to "Select/Approve" student applications and has a limited amount of freshman they can allow in; go through a similar process as the academies. The only difference is that they don't set aside "X" amount of slots for each representative, presidential, ROTC, prior enlisted, etc... But they do look at what state you're from, gender, race,, classes taken vs classes available, class rank, leadership, athletics, extra curricular, etc.... Hope some of this helps and makes sense. Best of luck. Mike......