Reply to More info on common lottery algorithm

Forum Index » DC Public and Public Charter Schools

Reply to "More info on common lottery algorithm"

Subject:

Emoticons





More smilies

Text Color: Font: Close Marks

[quote=Anonymous][quote=Anonymous][quote=Anonymous][quote=Anonymous][quote=Anonymous][quote=Anonymous]I had this conversation with people from the Common Lottery helpline a month ago - I brought up that I noticed last year, because you could click on your DCPS desired school's admit and waitlist and then click on the random assigned numbers of the people ahead of you to see hwo they'd ranked their schools - and when I looked at most of the people who were in single digits, they were on single digits on ALL or MOST of their waitlists.  Whereas many people who were #320 on one had sucky sucky 200s-300s numbers for all their choices too.  It wasn't true 100%, but it was true enough at the many random people I looked at, and it was true of us (but we were lucky to have our numbers all be in the teens and 20s).  The lottery staff said "No no that won't happen again this year", but really, it will, because preference people had preference before, and they do now, and there will be a computer attempt to go down each person's desired rankings, but at the end of the day the computer will use random lottery number, NOT desired school ranking, to choose between people who otherwise everything else is equal.  With the exception of the number of people who previously would have applied to 20 charters and now have to rank most of them along with DCPS (and the double/triple spot-holding that that leads to), it really doesn't sound like it's that much different in terms of giving you a better chance at YOUR #1 ranked school.  But my understanding from the school lottery folks was that you DID have a better chance under this model.[/quote]

Thanks for this explanation, it is the first thing that seems reasonably clear to me.  It also makes it abundantly clear that this system will be worse for individuals than applying to all of the school separately. At least in separate lotteries, I have an "new" chance of getting a good or bad lottery number for every school that we apply to.  If I get shut out in one place, I could still have a shot somewhere else. This explanation makes it seem like with the common lottery, there will be one random good or bad number that will either give me an excellent shot at all of my choices or a terrible shot at all of my choices.  The moment all the most coveted spots are filled, a few people will have the top spots on waiting lists for all the most coveted schools. By the same token, the same sad folks will be together in the bottom of all of the lists.  [/quote]

Hi, I'm the PP you're responding to.  I think there's actually better news than this - if you keep reading the conversation past this post, it sounds like actually, even if the computer randomly assigns you #312 for the lottery and that stays your lottery number, you are not in fact #312 and everyone between #1-#311 has a better shot than  you.  From what I'm reading above, that is NOT how it will work.

If I understand the above, even if your random assigned number is #312, it's possible you could be #2 on the waitlist for your 1st or 2nd choice school and the person with random lottery #3 could end up #235 on a waitlist.  It sounds like for each school, the computer looks at preference groups (i.e. everyone with sibling preference, or everyone with no preference at all) and within that preference group, for that school, does a random shuffle to establish the slots and waitlist.  So no matter what your assigned lottery number (i.e. 312), you could end up #4 ont he waitlist for one school, number 87 on the waitlist for another school, and #452 for a 3rd school.

So if what's said above is true, actually your randomly assigned number does NOT condemn you to unifrom suckiness or awesomeness.  It's a different shuffle for each school, even though your random number stays the same.[/quote]

What you are reading above is not correct. There is no "random shuffle." That's just wishful thinking.[/quote]

I am a statistician and know all about the deferred acceptance algorithm--you are incorrect. Please do some reading on this before you spread misinformation. And I don't know why you would think it to be "wishful thinking." It is simple statistics--doesn't make it any better for the chances that I, you, or anyone else will get in.[/quote]

I'm very happy for you. The FAQ makes it clear that there is no random shuffle. They may be using the term "deferred acceptance" improperly, but there is one draw, and that lottery number is used throughout.[/quote]

Options

	Disable HTML in this message
	Disable BB Code in this message
	Disable smilies in this message

Review message

Search Recent Topics Hottest Topics