Fairness of Common Lottery?

[Anonymous]

Anonymous wrote:

Anonymous wrote:

So really what the algorithim (sp?) should do is (preferences aside for the moment) run a lottery for everyone who ranked school A #1, then everyone who ranked school B #1, etc. Then after all the #1 rankings are run, they do another round (starting with whatever number they left off at at the end of the #1 rankings) for those who ranked the school #2. That way wouldn't you fill up all the most desireable schools only with people who ranked it first? And order the waitlist in groupings by where others ranked it? It would make the rankings much more meaningful. Would that lead to 12 separate lotteries for each school? That sounds like a technical nightmare but hey, computers are smart and can do just about anything, so isn't it possible?

The problem with that process is that if you don't get your number one you go down to the bottom of the list and you don't get another whack until the #2 round. So it's a real risk to put a popular school number one, if you don't get it by the time the lottery comes back to you everything is taken and you get nothing. So you might be tempted to put a "safety school" number one. But what if you get a good number and it's wasted on the safety school?

With the current system, you rank your choices in your true order of preference, and you get into the highest-ranked one that is available when your number comes up. No fiddling with the order changes your chances of getting picked. Since there is no "safety school" strategy, overall more people end up higher preference schools.

The problem with the lottery isn't its fairness. It is as fair as can be. The problem is the lack of good choices. People aren't ending up with no good choices because good seats are going unfilled or some children are occupying more than one. People are ending up with no good choices because there aren't enough for everyone. No amount of fiddling with the lottery is going to change that.

I'll add that before the common lottery schools ran their own lotteries, and there were unfilled seats at desirable schools. That has largely been eliminated.

I don't understand this. If you don't get matched in round 1 for your #1, you go on the waitlist, just like now. The difference/advantage to this proposal above is that you still will always have a better waitlist number than anyone who ranked it #2. And if you're not admitted, the algorithm keeps going down your list to your safeties, although if there were enough people who ranked your safety #1 you won't get in there either. But that's still a better system than the current system, because currently if you have a great random lottery number, even if you don't get into your #1, 2 or 3 you can get matched with your #4, even though lots of people may have put your #4 as #1. But no matter what order I rank schools in, if my random lottery number is crappy, I don't have a chance at my #1 school. Under the current system you can still end up with people at their #4 or #8 school, even though someone else with a worse # ranked your #8 as #1 or #2.

[Anonymous]

The system is designed for people to rank their TRUE preference and not try to game out others on their choose. (The only exception being the choice to include safety schools at the bottom of your list.)

[Anonymous]

Anonymous wrote:The system is designed for people to rank their TRUE preference and not try to game out others on their choose. (The only exception being the choice to include safety schools at the bottom of your list.)

What has anyone suggested about revising the new common lottery that indicates gaming the system?

[Anonymous]

I think I would have preferred the old system as well - not just because we've had poor draws the last 2 years. Even if we'd had our number 1 pick, I probably would have wondered if we should have ranked the schools differently. The winter months are such a whirlwind of open houses and researching schools you may have zero chance of being admitted to. It's really hard to gage whether or not a school (primarily the non-neighborhood and non-traditional schools) would work for your family when you have nothing more to rely on besides packed open houses (some of which don't even include classroom visits) and the rare current parent who is willing to give you an honest opinion.

I think I would have preferred applying separately to schools that interested us, then having an opportunity for an in-depth meet and greet and tour for admitted parents and those with high waitlist numbers, and could then decide whether or not to accept, although I understand the admittance process dragged on longer that way.

[Anonymous]

Not that one should always defer to expertise, but you do realize the group that developed the DC lottery system was headed by a guy who won a Nobel Prize in mathematics for the algorithm because it optimizes allocations.

But I bet you guys can come up with a better one chit chatting here.

[Anonymous]

Look up Alvin Roth and deferred acceptance.

[Anonymous]

And the Nobel was in economics not mathematics. My apologies.

[Anonymous]

Anonymous wrote:And the Nobel was in economics not mathematics. My apologies.

In true DCUM fashion, I will point out that there is no Nobel in economics. But we know which award you are referring to.

[Anonymous]

Anonymous wrote:

Anonymous wrote:And the Nobel was in economics not mathematics. My apologies.

In true DCUM fashion, I will point out that there is no Nobel in economics. But we know which award you are referring to.

Are you referring to the fact that it's officially the Nobel prize in economic sciences? That's really splitting hairs, particularly since it's often referred to as the Nobel prize in economics.

[Anonymous]

Yeah, I think the real takeaway of doing the lottery any other way is that people would try to strategize about how to order their picks.

[Anonymous]

Anonymous wrote:Not that one should always defer to expertise, but you do realize the group that developed the DC lottery system was headed by a guy who won a Nobel Prize in mathematics for the algorithm because it optimizes allocations.

But I bet you guys can come up with a better one chit chatting here.

Riiiight... because *every* conversation on DCUM is people thinking others will go and do exactly what they say...

Maybe have a glass of wine or take a yoga class, cuz you clearly are a little extra sensitive.

[Anonymous]

Anonymous wrote:Yeah, I think the real takeaway of doing the lottery any other way is that people would try to strategize about how to order their picks.

This is the silliest thing ever. Figuring out which school you want most and how to rank your schools to maximize your chances of getting in is the whole point. Making the rankings matter more just emphasizes that. The more your ranking influences your chances, the more careful and thoughtful people will be about how they rank. There's no way to "game" that, why are some people so extra super duper worried that parents will try to figure out how to get their kids into the school they think is best? Isn't that the entire point of ranking your choices?

[Anonymous]

Anonymous wrote:

Anonymous wrote:The system is designed for people to rank their TRUE preference and not try to game out others on their choose. (The only exception being the choice to include safety schools at the bottom of your list.)

What has anyone suggested about revising the new common lottery that indicates gaming the system?

Under the current system, you can't improve your chances of getting into a school by a different ranking. Under the change being proposed, you can. That's gaming.

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:The system is designed for people to rank their TRUE preference and not try to game out others on their choose. (The only exception being the choice to include safety schools at the bottom of your list.)

What has anyone suggested about revising the new common lottery that indicates gaming the system?

Under the current system, you can't improve your chances of getting into a school by a different ranking. Under the change being proposed, you can. That's gaming.

To me it's absurd to call it "gaming", but semantics aside, please explain clearly why making the rankings matter is gaming? If you don't have a shot at your #1 (if it's popular) unless you rank it #1, why in the world is that bad? Regardless of what name you want to call it and the judgements you want to apply to it, explain how increasing the likelihood that a higher % of families ranked their matched school #1 is in any way a bad thing or undesireable thing?

[Anonymous]

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:The system is designed for people to rank their TRUE preference and not try to game out others on their choose. (The only exception being the choice to include safety schools at the bottom of your list.)

What has anyone suggested about revising the new common lottery that indicates gaming the system?

Under the current system, you can't improve your chances of getting into a school by a different ranking. Under the change being proposed, you can. That's gaming.

To me it's absurd to call it "gaming", but semantics aside, please explain clearly why making the rankings matter is gaming? If you don't have a shot at your #1 (if it's popular) unless you rank it #1, why in the world is that bad? Regardless of what name you want to call it and the judgements you want to apply to it, explain how increasing the likelihood that a higher % of families ranked their matched school #1 is in any way a bad thing or undesireable thing?

The current lottery is designed so that no voluntary trades are possible. What that means is there is no outcome where two families look at their results and say "I'll trade my spot at school X for your spot at school Y" and both are better off. The reason this is true is that one of these families was ranked higher than the other in the lottery. If the higher-ranked family got school X and the lower family got school Y, then both X and Y were available to the higher-ranked family -- that's the way the lottery works. The higher-ranked family got X because they ranked X over Y. Ergo they are not voluntarily going to trade X for Y.

That's the theory.

What this leaves out is intensity of feeling, which I think is where the PP is coming from. What if the higher-ranked family is actually pretty ambivalent about X and Y, and only slightly prefers X, while the lower-ranked family really, really wants X and loathes Y. There would be a net increase in satisfaction if the higher family were forced to take Y over X and their spot was given to the lower family. In purely utilitarian terms this would be more optimal. In many circumstances people would voluntarily make this switch if it were explained to them, people do small favors all the time even for strangers if it doesn't cost them anything.

The problem with this enhancement isn't theoretical, it's practical. How do you gauge other people's utility? The proposed solution -- giving extra consideration to a #1 pick -- isn't nearly subtle enough. What if I'm OK with my number one through three picks, but four or lower would cause me to move out of DC. Should someone with a lower lottery number get my spot at my number three school just because they ranked it number one? Even if their number two is a perfectly reasonable alternative?