Anonymous wrote:

Anonymous wrote:Sorry to interrupt stats class, but back to the original post: we got shut out for K. Will go to IB school until we can move.

Can you share your list? That might actually be helpful for future years.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:What is the "switching" problem? I have no desire to read 25 pages to see if this term is defined. It was not in the cited page.

There's a mechanism to switch options if two kids are admitted to different schools but they each have a higher preference for the other. If you run separate lotteries you can't do that, as you would have to jump the waitlist to pull a kid up. With a unified lottery it works out and benefits both parties.

All of this was gone over in that thread. There are still only x number of seats for y number of students. The common lottery does not change the odds of you getting in to any school. It just simplifies the process, prevents shuffling, and distills your odds into a single number, instead of a whole bunch spread out over different waitlists. When you enter your odds are the same under either system.

Where is your cite for this being how the Common Lottery was run this year? In the bazillion threads on this (including some people who were specifically speaking to Common Lottery staff about it), it was made crystal clear that that switching wasn't happening, which actually is a huge bummer. It was clarified over and over again that the ONLY way that your own ranking of the schools on your list matters to what school you actually end up in is that if you get into one of your higher choices, you are dropped from consideration for all choices below.

You are describing a system where, once the lottery does it's thing, the program actually looks to see how everyone ranked their choices and where one student got a slot at a school they ranked #4 and another student got a spot at a different school they ranked #4, the computer would look at their higher choices to see if each student ranked the other student's school 1-3, and if so, swtich the students so they get one of their better choices. Nothing anyone said as the lottery was being rolled out indicated that this "switching" was going to happen. I really like the idea of switching, but it was made pretty clear that wasn't part of the actual process this year.

What is your source for saying that indeed that is what happened?

New poster, I believe you are correct. I think the system doesn't have "mutually beneficial trades" because under the algorithm there are no equivalent swaps. There will always be one student that has a better combination of number+preference so there's no need to trade.

(not a stats person, so please correct me if wrong)

Anonymous wrote:

Anonymous wrote:
Different PP than the one you're responding to, but while the points you make are true, you are still missing the prior PP's point, which is also true. Even though not every student will be in every pool, for whatever pool you ARE in, having a bad number shuts you out of everything, usually even you're #12 choice. Whereas before, even if you still only applied to 12 schools, 12 different lotteries meant you had a brand new chance at a good number in each lottery. That, in and of itself, improves the odds you'll do well. Doesn't increase the spots, doesn't reduce the number of applicants overall. But in each lottery it means you have a new chance to do well, as opposed to just one shot to do well that impacts all your choices.

Not saying one system is better than the other, just pointing out that it is INcorrect to say the odds are the same under both systems. They are not the same.

This is wrong. I explained why using math. The example I gave was simple, but the same result occurs with different numbers.

Anonymous wrote:Sorry to interrupt stats class, but back to the original post: we got shut out for K. Will go to IB school until we can move.

Anonymous wrote:
Different PP than the one you're responding to, but while the points you make are true, you are still missing the prior PP's point, which is also true. Even though not every student will be in every pool, for whatever pool you ARE in, having a bad number shuts you out of everything, usually even you're #12 choice. Whereas before, even if you still only applied to 12 schools, 12 different lotteries meant you had a brand new chance at a good number in each lottery. That, in and of itself, improves the odds you'll do well. Doesn't increase the spots, doesn't reduce the number of applicants overall. But in each lottery it means you have a new chance to do well, as opposed to just one shot to do well that impacts all your choices.

Not saying one system is better than the other, just pointing out that it is INcorrect to say the odds are the same under both systems. They are not the same.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:The same number of students get into the desirable spots either way in this scenario. Thus, every student still has the same chance to get one of the 12 spots. The only difference is that with one lottery you know earlier whether you got into your chosen school, a different school, or got shut out.

You still don't understand the difference between one single student's odds of getting into 12 schools in 12 different lotteries vs. 12 schools in 1 lottery. No one is arguing the fact that at the end of the day, there are only X number of spots with Y numbers of people looking and only X students will end up in those spots. Yes, we all understand that part.

Each lottery is for only a fraction of the total pot. Thus the chances in each individual lottery are less than the chances of getting into any of the schools in the larger lottery.

Ex. 2 schools, 1 space in each. 10 students applying. If there are two lotteries, the student has a 1 in 10 chance of getting into school A and a 1 in 10 chance of getting into school B. Thus, the student has a 2 in 10 (1 in 5) chance of getting into either school. If there is one lottery, the student has a 2 in 10 (or 1 in 5) chance of getting into one of the schools. See how it is the same. Do you need another example?

You're assuming that all things are equal in this example. They are not. Under the old system, child had a 1 in 10 chance at one school and a 1 in 500 chance at another school and each of those odds operated independently of each other. Under the new system with the single draw, a poor number rules them out of every single option, even the ones where the odds would have been pretty good.

But you are missing part of the equation. First, because you can only choose 12 schools, not every student will be in every pool. That reduces the size of some pools. And secondly, after each round, a certain number of students have been matched and are no longer in the pools, thereby increasing the odds of a match for students who are still in the mix.

Different PP than the one you're responding to, but while the points you make are true, you are still missing the prior PP's point, which is also true. Even though not every student will be in every pool, for whatever pool you ARE in, having a bad number shuts you out of everything, usually even you're #12 choice. Whereas before, even if you still only applied to 12 schools, 12 different lotteries meant you had a brand new chance at a good number in each lottery. That, in and of itself, improves the odds you'll do well. Doesn't increase the spots, doesn't reduce the number of applicants overall. But in each lottery it means you have a new chance to do well, as opposed to just one shot to do well that impacts all your choices.

Not saying one system is better than the other, just pointing out that it is INcorrect to say the odds are the same under both systems. They are not the same.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:The same number of students get into the desirable spots either way in this scenario. Thus, every student still has the same chance to get one of the 12 spots. The only difference is that with one lottery you know earlier whether you got into your chosen school, a different school, or got shut out.

You still don't understand the difference between one single student's odds of getting into 12 schools in 12 different lotteries vs. 12 schools in 1 lottery. No one is arguing the fact that at the end of the day, there are only X number of spots with Y numbers of people looking and only X students will end up in those spots. Yes, we all understand that part.

Each lottery is for only a fraction of the total pot. Thus the chances in each individual lottery are less than the chances of getting into any of the schools in the larger lottery.

Ex. 2 schools, 1 space in each. 10 students applying. If there are two lotteries, the student has a 1 in 10 chance of getting into school A and a 1 in 10 chance of getting into school B. Thus, the student has a 2 in 10 (1 in 5) chance of getting into either school. If there is one lottery, the student has a 2 in 10 (or 1 in 5) chance of getting into one of the schools. See how it is the same. Do you need another example?

You're assuming that all things are equal in this example. They are not. Under the old system, child had a 1 in 10 chance at one school and a 1 in 500 chance at another school and each of those odds operated independently of each other. Under the new system with the single draw, a poor number rules them out of every single option, even the ones where the odds would have been pretty good.

But you are missing part of the equation. First, because you can only choose 12 schools, not every student will be in every pool. That reduces the size of some pools. And secondly, after each round, a certain number of students have been matched and are no longer in the pools, thereby increasing the odds of a match for students who are still in the mix.

Different PP than the one you're responding to, but while the points you make are true, you are still missing the prior PP's point, which is also true. Even though not every student will be in every pool, for whatever pool you ARE in, having a bad number shuts you out of everything, usually even you're #12 choice. Whereas before, even if you still only applied to 12 schools, 12 different lotteries meant you had a brand new chance at a good number in each lottery. That, in and of itself, improves the odds you'll do well. Doesn't increase the spots, doesn't reduce the number of applicants overall. But in each lottery it means you have a new chance to do well, as opposed to just one shot to do well that impacts all your choices.

Not saying one system is better than the other, just pointing out that it is INcorrect to say the odds are the same under both systems. They are not the same.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:The same number of students get into the desirable spots either way in this scenario. Thus, every student still has the same chance to get one of the 12 spots. The only difference is that with one lottery you know earlier whether you got into your chosen school, a different school, or got shut out.

You still don't understand the difference between one single student's odds of getting into 12 schools in 12 different lotteries vs. 12 schools in 1 lottery. No one is arguing the fact that at the end of the day, there are only X number of spots with Y numbers of people looking and only X students will end up in those spots. Yes, we all understand that part.

Each lottery is for only a fraction of the total pot. Thus the chances in each individual lottery are less than the chances of getting into any of the schools in the larger lottery.

Ex. 2 schools, 1 space in each. 10 students applying. If there are two lotteries, the student has a 1 in 10 chance of getting into school A and a 1 in 10 chance of getting into school B. Thus, the student has a 2 in 10 (1 in 5) chance of getting into either school. If there is one lottery, the student has a 2 in 10 (or 1 in 5) chance of getting into one of the schools. See how it is the same. Do you need another example?

You're assuming that all things are equal in this example. They are not. Under the old system, child had a 1 in 10 chance at one school and a 1 in 500 chance at another school and each of those odds operated independently of each other. Under the new system with the single draw, a poor number rules them out of every single option, even the ones where the odds would have been pretty good.

But you are missing part of the equation. First, because you can only choose 12 schools, not every student will be in every pool. That reduces the size of some pools. And secondly, after each round, a certain number of students have been matched and are no longer in the pools, thereby increasing the odds of a match for students who are still in the mix.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:What is the "switching" problem? I have no desire to read 25 pages to see if this term is defined. It was not in the cited page.

There's a mechanism to switch options if two kids are admitted to different schools but they each have a higher preference for the other. If you run separate lotteries you can't do that, as you would have to jump the waitlist to pull a kid up. With a unified lottery it works out and benefits both parties.

All of this was gone over in that thread. There are still only x number of seats for y number of students. The common lottery does not change the odds of you getting in to any school. It just simplifies the process, prevents shuffling, and distills your odds into a single number, instead of a whole bunch spread out over different waitlists. When you enter your odds are the same under either system.

Where is your cite for this being how the Common Lottery was run this year? In the bazillion threads on this (including some people who were specifically speaking to Common Lottery staff about it), it was made crystal clear that that switching wasn't happening, which actually is a huge bummer. It was clarified over and over again that the ONLY way that your own ranking of the schools on your list matters to what school you actually end up in is that if you get into one of your higher choices, you are dropped from consideration for all choices below.

You are describing a system where, once the lottery does it's thing, the program actually looks to see how everyone ranked their choices and where one student got a slot at a school they ranked #4 and another student got a spot at a different school they ranked #4, the computer would look at their higher choices to see if each student ranked the other student's school 1-3, and if so, swtich the students so they get one of their better choices. Nothing anyone said as the lottery was being rolled out indicated that this "switching" was going to happen. I really like the idea of switching, but it was made pretty clear that wasn't part of the actual process this year.

What is your source for saying that indeed that is what happened?

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:We got nothing in the first round or the second round, so we're sticking with daycare for another year. Can't help but think that the previous system would have been better for us.

You clearly never went through the previous system.

BS. I went through the previous system and can tell you that EVERYONE I know got in somewhere they were happy with for PS3. EVERYONE. In fact most of us had multiple offers. Sure, we may have been less likely to get in at our number one pick, but we got multiple offers. This time around, if you got a bad draw in the lottery you were shut out of everywhere.

For us, it worked okay. For PS3 we had offers for Bridges, Appletree, DC Prep and a couple of others, as well as our inbound. For K we played again now with the common lottery and were shut out initially and hovered around the 50 percent mark on all the wait lists. Got in to our number 5 pick in May and happy there (so far). Still, for most people under the old system so long as you applied everywhere your chances of being shut out were minimal.

I find this perspective odd as there are the same number of slots for children in the old system as well as the common lottery, and therefore the same number shut out either way. I guess last year your friends were just all lucky.

Not talking about "last year" but talking about the last 5 years.

Anonymous wrote:

Anonymous wrote:What is the "switching" problem? I have no desire to read 25 pages to see if this term is defined. It was not in the cited page.

There's a mechanism to switch options if two kids are admitted to different schools but they each have a higher preference for the other. If you run separate lotteries you can't do that, as you would have to jump the waitlist to pull a kid up. With a unified lottery it works out and benefits both parties.

All of this was gone over in that thread. There are still only x number of seats for y number of students. The common lottery does not change the odds of you getting in to any school. It just simplifies the process, prevents shuffling, and distills your odds into a single number, instead of a whole bunch spread out over different waitlists. When you enter your odds are the same under either system.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Okay, you win, statistics moron. Let's go back to a system in which everyone has an equal chance to land a desirable spot, but the spots they land are not desirable to them. Great plan.

Childish namecalling aside, another issue you clearly don't understand is the difference between working to improve the overall number of quality spots available (which is essential obviously in DC), and just pointing out basic facts about the pluses and minuses about different application/lottery systems. Those are two totally different issues, even though the overwhelming demand compared to the small supply is a root cause for both.

You're too petty to pay attention to the fact that it's possible to both be in favor of the common lottery (which I am), AND to recognize that there is a drawback, namely that actually individual odds of getting in to one of the better schools are reduced if there's one draw. Good luck with just spinning around on namecalling and oversimplication. Hopefully others are actually able to recognize the pluses and minuses and keep working to improve BOTH the number of quality school spots available (by improving the schools we already have and opening new schools where necessary, both complex but crucial endeavors) as well as by improving the application system each year.

THANK YOU! Of course those of us who are smart would never call PP a "moron" no matter what the evidence might suggest.

You do realize I'm reading this and attempting to engage in a discussion based on my perceptions, prior discussions, anecdotal scenarios and my apparently very limited grasp of statistics, right? How does being snarky and personally attacking me (with your "evidence" and all) contribute to this? And, no, I'm not new to DCUM and have seen many a thread devolve into this crap. It's ridiculous.

I'm also in favor of the common lottery and see its benefit clearly. I also know that the prior system had advantages, which I've explained based on my experience. We did not take the spot offered to us because changing circumstances made the logistics a little more difficult than anticipated and because we had the option to remain in our preschool another year. Entering the lottery this year was a totally different experience and we got shut out. I'm not bitching, I'm not name calling, I'm not pointing fingers. Someone has to be last. Just knock off the bitchiness for a second or two and try to contribute.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:The same number of students get into the desirable spots either way in this scenario. Thus, every student still has the same chance to get one of the 12 spots. The only difference is that with one lottery you know earlier whether you got into your chosen school, a different school, or got shut out.

You still don't understand the difference between one single student's odds of getting into 12 schools in 12 different lotteries vs. 12 schools in 1 lottery. No one is arguing the fact that at the end of the day, there are only X number of spots with Y numbers of people looking and only X students will end up in those spots. Yes, we all understand that part.

Each lottery is for only a fraction of the total pot. Thus the chances in each individual lottery are less than the chances of getting into any of the schools in the larger lottery.

Ex. 2 schools, 1 space in each. 10 students applying. If there are two lotteries, the student has a 1 in 10 chance of getting into school A and a 1 in 10 chance of getting into school B. Thus, the student has a 2 in 10 (1 in 5) chance of getting into either school. If there is one lottery, the student has a 2 in 10 (or 1 in 5) chance of getting into one of the schools. See how it is the same. Do you need another example?

You're assuming that all things are equal in this example. They are not. Under the old system, child had a 1 in 10 chance at one school and a 1 in 500 chance at another school and each of those odds operated independently of each other. Under the new system with the single draw, a poor number rules them out of every single option, even the ones where the odds would have been pretty good.