Reply to More info on common lottery algorithm

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[quote=Anonymous][quote=Anonymous][quote=Anonymous][quote=Anonymous][quote=Anonymous][quote=Anonymous][quote=Anonymous]So do you get one, single randomly assigned lottery number that applies to all 12 of your selections?  Or are you entered essentially into almost 12 separate lotteries for each school, with a random assigned number for that school?

Man would it SUCK to get a crappy number for all 12 choices.  Wouldn't that essentially (unless you have both IB and sibling preference for your 1st choice or something) knock you out of the whole lottery because, at least for the more popular schools, there is guaranteed to be more people with better numbers who ranked it high enough to be competing with you?[/quote]

Your lottery number is not the same for all schools, so your second scenario is not accurate. No worries there. But it's not exactly as simple as each school running a separate lottery, because rather than having the schools run the lottery and then choose the students, the students in the algorithm do the requesting of the spot. They are temporarily assigned and reassigned in many rounds. In the end, your relative waitlist number will vary in the schools you apply to because their "rank" of you depends first on preference (they will always choose someone who is IB over someone who is OOB, e.g.) and then, within that preference band, by random lottery number.

As PP said, all you need to do is list in the order of preference.[/quote]

Sorry, should have been more clear - your lottery number ORDER is not the same for all schools. Meaning, within preference catgories, each school then randomly chooses an order for the people who have applied. So you could be without a sibling at TR and have a relatively good spot on the waitlist and without a sibling at MV and be in a terrible waitlist position.[/quote]

The last part was already clear.  Here is what's not:

Say I have NO preference for any school (and not applying to my IB school).  And say my #1 choice is Ross (random name that came to me) and my #2 choice is Bancroft.  Am I given one single lottery number which will apply to both Ross and Bancroft, even though who I'm up against in each is obviously diffferent?  Or will the computer look at all the students with no preference requesting Ross, assign random lottery numbers to all those requests, assign/waitlist, and then if I don't get in to Ross, the computer then looks at all the no preference people requesting Bancroft, assigns a random lottery number to each person in THAT pool of requests, and assigns/waitlists for that pool, etc until it successfully matches me or runs out of options and I'm waitlisted everywhere?

The latter scenario would be an improvement over last year.  Not sure though that the 1st scenario really adds much fairness though.[/quote]

Here's how it would work.

Let's say your first choice is Ross and second choice Bancroft.

In round 1 of the lottery, you request Ross, and everyone else requests their first choice school. Each school then goes through and accepts or rejects applicants. (This is all done by computer, of course.) Each school has ranked each student according to preference first and then a randomly after that. So if you are OOB for Ross, but a lot of IB people put them as their #1 choice, then you are definitely not going to get in. But, let's say that Ross families put Ross further down their list -- let's say 4 or 5 -- and among the OOB families, you are pretty high on Ross's list --then maybe you get a TEMPORARY assignment at Ross in Round 1.

In round 2, all the people who weren't matched in round 1 bid on their next choice school. Let's say some of the IB ross people have put Ross as #2. Ross then considers all the people they accepted in round 1 and all the people who bid in round 2 and makes decisions. So, if you are IB for Ross, even though someone OOB was assigned in round 1, you trump them. The OOB person gets bumped and you get the spot.

So, then, let's say you don't get into Ross, in Round 3 you bid on your next choice school, which is Bancroft. The same thing happens--you are compared with all the people who have bid in this round and all the people who were temporarily accepted in prior rounds. Etc. etc. etc.

What this shows is that:

1) Schools will have randomly generated waitlists within each category. So, someone who is OOB w/sibling will definitely have a better waitlist # than someone who is with no preference, but within the no preference category, the waistlist will be random.

2) Each school has a different random lottery order within each category. So, at Ross as OOB you might have a relatively good # (say, the #2 OOB person, just from random order), and at Bancroft you could have a relatively bad # (say, the #120 OOB person, just from random order).

3) It is definitely possible because of the randomization of the order from the schools for mutually beneficial trades to occur. Example: I get into A, you get into B. I prefer B to A; you prefer A to B. The computer could trade us so we are both in our top-ranked choice. Not sure whether DC will do this.

4) It definitely makes sense to rank order in terms of your true preferences BUT

5) If you definitely want a spot, you need to think of schools where you are likely to get in. Think of schools that went through their whole waitlists last year, your IB school. My spouse and I thought we would never apply to our IB school but then were pleasantly surprised at the open house. Knowing more about how the lottery works, I would not waste an OOB spot on a school like Ross or even Bancroft--which didn't accept any oob students as of count day. I am using my spots carefully, and my #12 spot will go to my IB school.

Good luck![/quote]

This is not how DC works.  There is no randomization by the schools. Your one lottery number is your number for every school.[/quote]

You are mistaken. The above is EXACTLY how the deferred acceptance algorithm cited in the q and a works.[/quote]

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