Common Lottery Algorithm

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:I am getting confused. I thought the algorithm doesn't weight the parents' ranking, but lots of people are saying now that it does.

You thought right, and they thought wrong.

Ha, okay. Wishful thinking on some people's part that putting #1 is going to help. Thanks.

Right, because somehow your opinion on this is more legitimate than what actual authorities involved this year, in this lottery in this are saying... Ha, okay.

Here's what putting a school at #1 does - it makes it your #1 school choice. If you get accepted in it, then great. If you don't then it moves down the line. It says, "I prefer this over the other schools I selected, so if I get in, I want to keep it". Your #2 school says "I prefer this over the other schools I selected accept for #1, and if I get into #2 then great! If I get into #1 then disregard #2 and give me #1".

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:I am getting confused. I thought the algorithm doesn't weight the parents' ranking, but lots of people are saying now that it does.

A lot of people are saying a lot of things. What I will point out is, regardless of what the different perspectives here are, if you talk to the Common Lottery staff and staff at some of the participating schools, they all say that the parent's ranking DOES matter and can influence the results. No one, and I mean no one that I have talked to about this who's actually directly involved has said that the parent's ranking doesn't matter.

The specifics of how the algorithm works, where/when ranking comes into play... lots of opinions about that. But no one official in this has said that parent ranking doesn't influence the results, and some schools (including Mundo Verde on their admissions page of their official website) are saying ranking DOES matter. That is why this is considered "2-way matching", trying to match the people the schools are prioritizing with the people prioritizing that school.

Not really. They are saying "Rank us #1 to increase your chances." If I rank Mundo Verde #3, and I get in to my 1 or 2 choice, then I am completely off the Mundo Verde list. I have lost any chance of attending the school. If I want to guarantee a CHANCE to get in any given school, I need to rank that school #1. So yes, ranking obviously matters. It matters a lot. However, it does not mean that ranking the school a school #1 adds a weight to my chances of getting in to that school.

This is logic at its finest.

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:I am getting confused. I thought the algorithm doesn't weight the parents' ranking, but lots of people are saying now that it does.

You thought right, and they thought wrong.

Ha, okay. Wishful thinking on some people's part that putting #1 is going to help. Thanks.

Right, because somehow your opinion on this is more legitimate than what actual authorities involved this year, in this lottery in this are saying... Ha, okay.

Regardless, it doesn't change my ranking strategy. I think the effect of all this discussion is only changing people's perceptions of their chances or ability to control their own destiny; i.e. their special #1 pick might be enough to get them in.

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:I am getting confused. I thought the algorithm doesn't weight the parents' ranking, but lots of people are saying now that it does.

You thought right, and they thought wrong.

Ha, okay. Wishful thinking on some people's part that putting #1 is going to help. Thanks.

Right, because somehow your opinion on this is more legitimate than what actual authorities involved this year, in this lottery in this are saying... Ha, okay.

Here's what putting a school at #1 does - it makes it your #1 school choice. If you get accepted in it, then great. If you don't then it moves down the line. It says, "I prefer this over the other schools I selected, so if I get in, I want to keep it". Your #2 school says "I prefer this over the other schools I selected accept for #1, and if I get into #2 then great! If I get into #1 then disregard #2 and give me #1".

That is obvious. No one in any of these threads is disputing this.

The question is, beyond that, are there any points in the process where how you rank the school gives you an edge or a disadvantage over other students in your preference category that the computer is considering. That is where people have varying opinions, and anyone who's spoken to the Common Lottery has been told that it matters, because the goal is to match schools with the students they prioritize (sibs, IB, AND those who actually really want to be at that school) with those who show they really want to be at that school.

Call. Ask. Regardless of any other variations in answers that people are getting, this has not changed in the answers.

[Anonymous]

Anonymous wrote:
NYC/Boston/Denver/New Orleans all use the same basic system with some slight differences.

The only differences would be the preferences awarded by the schools. DC uses IB for Pre-S/Pre-K. DC has different measurement for Proximity. DC has different rules for Sibling. DC just has different preferences. Everything else is the same between these school districts. They all use a deferred acceptance model. They all have the parents/children rank their schools. They all have the schools assign preferences to the children. They all use a stable match algorithm. They all do the same exact thing, they just use different data to model it.

[Anonymous]

Anonymous wrote:
That is obvious. No one in any of these threads is disputing this.

Are you reading the same thread? People are questioning this on every page. People are stating that the parent ranking hold the more weight then it actually does. Go back to each page and you'll find at least one post where someone is saying having a school ranked #1 gives you priority over someone who ranked it #2 but with a better preference. That is not at all true and misrepresents a stable matching algorithm.

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:I am getting confused. I thought the algorithm doesn't weight the parents' ranking, but lots of people are saying now that it does.

A lot of people are saying a lot of things. What I will point out is, regardless of what the different perspectives here are, if you talk to the Common Lottery staff and staff at some of the participating schools, they all say that the parent's ranking DOES matter and can influence the results. No one, and I mean no one that I have talked to about this who's actually directly involved has said that the parent's ranking doesn't matter.

The specifics of how the algorithm works, where/when ranking comes into play... lots of opinions about that. But no one official in this has said that parent ranking doesn't influence the results, and some schools (including Mundo Verde on their admissions page of their official website) are saying ranking DOES matter. That is why this is considered "2-way matching", trying to match the people the schools are prioritizing with the people prioritizing that school.

Not really. They are saying "Rank us #1 to increase your chances." If I rank Mundo Verde #3, and I get in to my 1 or 2 choice, then I am completely off the Mundo Verde list. I have lost any chance of attending the school. If I want to guarantee a CHANCE to get in any given school, I need to rank that school #1. So yes, ranking obviously matters. It matters a lot. However, it does not mean that ranking the school a school #1 adds a weight to my chances of getting in to that school.

So let's be clear: you are saying that once students are grouped by preference, and the algorithm is filling slots for a highly popular school for the sibling preference group, you are saying once you're in that group, the child who ranked the school #4 has an equal chance of getting the slot as the child who ranked the school #1? Assume #4 has already not gotten into their 1-3 choice. That is what you are saying, correct, that it's either equal chances or random at that point?

Not pp, but yes I believe that the child who ranked it #4 and the child who ranked it #1 have an ALMOST equal chance. The ALMOST has to do with the random lottery number they were assigned. If the child who ranked it #4 has a better lottery number (and is in the same preference pool) they will get the seat. If the child who ranked it #1 has a better lottery number (and is in the same preference pool) then they will get the seat.

Again, to be clear this is all based on the assumption that the child who ranked MV as #4 was locked out of #s 1-3.

Correct.

[Anonymous]

Yes, your #4 becomes your #1 if you strike out at 1-3, but the fact that you didn't rank your #4 school as #1 in the first place makes someone who actually ranked it #1 more likely to get it once the computer is sorting among your preference group for that school. You do not look like a #1 choice just because you're waitlisted at your 1-3 by the time the computer is considering you for your #4 school as compared to others for whom it was always #1.

This is an example of someone on the previous page who is mistating what the parent rank accomplishes. That bold sentence is not at all true. How other people rank the school has nothing to do with your acceptance. It has to do with how the school ranked you and others who applied to it. The parent ranking only comes into play when you get an acceptance at more than one school. You will only be accepted at one school and it determines that based on the highest ranking you provided. Once you are accepted to a school you will only be removed from it if someone with a HIGHER PREFERENCE (ie SIBLING > PROXIMITY > NO PREFERENCE) or someone with the same preference but a better lottery number (which technically wouldn't happen because assignments are done by lottery number).

[Anonymous]

Child #1 has sibling preference but ranked school ABC at #3, and didn't get into their #1-2.
Child #2 has no preferences but ranked school ABC at #1.

Who gets the seat at school ABC?

What if child #2's lottery number is higher than child #1's?

[Anonymous]

Anonymous wrote:
Child #1 has sibling preference but ranked school ABC at #3, and didn't get into their #1-2.
Child #2 has no preferences but ranked school ABC at #1.

Who gets the seat at school ABC?

What if child #2's lottery number is higher than child #1's?

Child #1. Sibling preference trumps no preference every time.

[Anonymous]

Anonymous wrote:

Anonymous wrote:
Child #1 has sibling preference but ranked school ABC at #3, and didn't get into their #1-2.
Child #2 has no preferences but ranked school ABC at #1.

Who gets the seat at school ABC?

What if child #2's lottery number is higher than child #1's?

Child #1. Sibling preference trumps no preference every time.

I second this. 100% according to the logic of stable match. School ABC prefers Child #2 over #1 so this creates an equitable match for all parties involved.

[Anonymous]

Anonymous wrote:

Anonymous wrote:
That is obvious. No one in any of these threads is disputing this.

Are you reading the same thread? People are questioning this on every page. People are stating that the parent ranking hold the more weight then it actually does. Go back to each page and you'll find at least one post where someone is saying having a school ranked #1 gives you priority over someone who ranked it #2 but with a better preference. That is not at all true and misrepresents a stable matching algorithm.

You conveniently cut out your post that I was responding to. Wow, are you that desperate to appear right?

Since you seem to have forgotten what you said:



Here's what putting a school at #1 does - it makes it your #1 school choice. If you get accepted in it, then great. If you don't then it moves down the line. It says, "I prefer this over the other schools I selected, so if I get in, I want to keep it". Your #2 school says "I prefer this over the other schools I selected accept for #1, and if I get into #2 then great! If I get into #1 then disregard #2 and give me #1".

You do not raise the bigger question that we are all arguing about in this quote. That is why THIS is obvious.

So, show ANYWHERE in this thread where the part of the process that you describe above is questioned?

[Anonymous]

Anonymous wrote:

Yes, your #4 becomes your #1 if you strike out at 1-3, but the fact that you didn't rank your #4 school as #1 in the first place makes someone who actually ranked it #1 more likely to get it once the computer is sorting among your preference group for that school. You do not look like a #1 choice just because you're waitlisted at your 1-3 by the time the computer is considering you for your #4 school as compared to others for whom it was always #1.

This is an example of someone on the previous page who is mistating what the parent rank accomplishes. That bold sentence is not at all true. How other people rank the school has nothing to do with your acceptance. It has to do with how the school ranked you and others who applied to it. The parent ranking only comes into play when you get an acceptance at more than one school. You will only be accepted at one school and it determines that based on the highest ranking you provided. Once you are accepted to a school you will only be removed from it if someone with a HIGHER PREFERENCE (ie SIBLING > PROXIMITY > NO PREFERENCE) or someone with the same preference but a better lottery number (which technically wouldn't happen because assignments are done by lottery number).

To everyone reading this, if believing one way or the other in any way changes how you rank, please, please, call the Common Lottery. That is the only explanation of whether a parent's ranking ever enters the equation (beyond what order the computer tries to fill your requests) you should trust. I say the bold sentence is true, the PP above says it's not... if which one you believe affects the way you rank, do not believe either. Go to the sources, either your #1 school or most relevant the Common Lottery staff themselves.

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:
That is obvious. No one in any of these threads is disputing this.

Are you reading the same thread? People are questioning this on every page. People are stating that the parent ranking hold the more weight then it actually does. Go back to each page and you'll find at least one post where someone is saying having a school ranked #1 gives you priority over someone who ranked it #2 but with a better preference. That is not at all true and misrepresents a stable matching algorithm.

You conveniently cut out your post that I was responding to. Wow, are you that desperate to appear right?

Since you seem to have forgotten what you said:

Here's what putting a school at #1 does - it makes it your #1 school choice. If you get accepted in it, then great. If you don't then it moves down the line. It says, "I prefer this over the other schools I selected, so if I get in, I want to keep it". Your #2 school says "I prefer this over the other schools I selected accept for #1, and if I get into #2 then great! If I get into #1 then disregard #2 and give me #1".

You do not raise the bigger question that we are all arguing about in this quote. That is why THIS is obvious.

So, show ANYWHERE in this thread where the part of the process that you describe above is questioned?

4 posts above this (from 11:49) provide an example from page 14 where someone gets it wrong and assume a parent who ranks a school as #1 has greater weight than a parent who ranks the same school as #4.

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:
That is obvious. No one in any of these threads is disputing this.

Are you reading the same thread? People are questioning this on every page. People are stating that the parent ranking hold the more weight then it actually does. Go back to each page and you'll find at least one post where someone is saying having a school ranked #1 gives you priority over someone who ranked it #2 but with a better preference. That is not at all true and misrepresents a stable matching algorithm.

You conveniently cut out your post that I was responding to. Wow, are you that desperate to appear right?

Since you seem to have forgotten what you said:

Here's what putting a school at #1 does - it makes it your #1 school choice. If you get accepted in it, then great. If you don't then it moves down the line. It says, "I prefer this over the other schools I selected, so if I get in, I want to keep it". Your #2 school says "I prefer this over the other schools I selected accept for #1, and if I get into #2 then great! If I get into #1 then disregard #2 and give me #1".

You do not raise the bigger question that we are all arguing about in this quote. That is why THIS is obvious.

So, show ANYWHERE in this thread where the part of the process that you describe above is questioned?

4 posts above this (from 11:49) provide an example from page 14 where someone gets it wrong and assume a parent who ranks a school as #1 has greater weight than a parent who ranks the same school as #4.
Look right above you for an example.