I think the 101 example is really helpful. I was talking to a current fellow at a program that was matching new fellows this past Wednesday, and he seemed to imply that if his program had rearranged its rank list of applicants, they would have filled all their spots (I think there were like 5 spots, filled 3). As my understand goes, that would't have happened no matter what--unless they ranked more applicants, they wouldn't have been more likely to fill all their spots.
Yup, a lot of people don't really get how the match process works.
Simple Example:
Ranks
Applicant A: 1. State, 2. County, 3. University
Applicant B: 1. State, 2. County, 3. University
Applicant C: 1. State, 2. County, 3. University
etc.
State - 2 spots: 1. App B, 2. App C, 3. App A
County - 1 spot: 1. App C, 2. App A, 3. App B
etc.
Match:
Round 1: App A goes first, wants state #1 and State ranked him and has a spot open. Applicant is matched.
Round 2: App B goes next, wants state #1 as well, State ranked App B higher than App A, App B is Matched, App A is still matched. All spots filled at program.
(This next step is what most people don't get, being "matched" is fluid until all possible match permutations are made).
Round 3: App C goes next, wants state #1 as well, State ranked C lower than B, B keeps spot, C is ranked higher than A, C takes A spot. A gets bumped to "rematch" list.
Round 4: App A goes again, wants state #1, all spots filled move to next rank, wants County #2, spot is open and applicant is ranked, A takes spot at County.
Repeat until all possible matches are made (no movement to rematch list or impossible match qualifications met)
This is why you rank programs the way YOU like them because the system is biased towards the applicant and their preferences. In the example above you see that County wanted App C as their number 1 pick, but because the applicant ranked them lower, the applicant already had a match for their #1 program. So if Applicant C thought that State was a "reach" but had a "guaranteed" spot at County and if they therefore ranked County higher they would have missed out on their chance to get into State. (i.e. Because County was always a sure thing as they ranked C highest, he would AT LEAST match there as long as he put them on his rank list ). As you can also see County "wasted" a rank (two actually) on someone that preferred another school, hence why the match is skewed towards the applicant as we have no "wasted" ranks.