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I'm going to repost the same comment I made on /r/math: > By trading places, students could get another shot at a place. At schools for which they already had

I'm going to repost the same comment I made on /r/math: > By trading places, students could get another shot at a place. At schools for which they already had a go in the lottery. This would give them better chances. At the expense of students that don’t (or can’t) trade. This is unfair. This argument here is not correct. It's not at anyone's expense. The two people trading both benefit, and other students are unaffected. Not everything is zero-sum; not every benefit is at somebody's expense! (The strategy argument -- that people had been explicitly told the system was strategy-free, and it would be wrong to go back on that guarantee by allowing trading -- makes much more sense.) This is an interesting article about social choice theory but the non-mathematical parts seem to be making some implicit assumptions about "fairness" that are, let's say, not exactly uncontroversial. And the argument I point out above is just in error.

deleted 9y ago
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cortesoft 9y ago
You are missing some key points - if they allow trading, they are going to incentivize people choosing popular schools instead of ones they actually want to go to. Since more people are going to choose popular schools in hopes of getting a good trading asset, people who ACTUALLY want to go to those popular schools are going to be less likely to get in. Your assertion that it is an 'error' is only true if they only allow the trading to happen this year (after the preferences were set), and not in future years. The trades are only pareto-superiour if there are no future decisions to be made; since this is a repeated game, allowing pareto-superior trades this year means that next years game will NOT be fair (by their definition of fairness). I agree that their definition of 'fairness' is not objective, but it is one they have decided to go with; they decided that the ability to strategize is not evenly distributed, and so allowing strategy is unfair.
- Sniffnoy 9y ago
  Yes, the incentives this sets up could be bad for subsequent rounds; that is absolutely a real problem, as I mentioned. But this passage seemed to be suggesting that trading, in and of itself, harmed students who were not involved in the trade, and that's not correct. Notice it explicitly says: > This would give them better chances. At the expense of students that don’t (or can’t) trade. But in fact those students are unaffected. In subsequent years, as you say, it is a problem. But I don't see how to read that part as anything other than denying that when just restricted to that year it is a Pareto-improvement. You may say "well that's a self-evidently stupid claim; of course they're not making that claim, because that would be stupid". But there's a lot of people out there who really seem to believe in a zero-sum world, and are convinced that when anyone's position improves, that means that everyone else has been harmed. That Pareto improvements are fundamentally impossible. There are absolutely people out there who would make that claim.
  - cortesoft 9y ago
    This IS a zero sum game, though. There are only x number of spots at each school. I agree that the wording of 'at the expense of' is a bit misleading, but I don't think it is categorically incorrect. The idea of fairness can, by certain definitions, even encompass pareto-superiour situation, if the improvements are not distributed fairly. I gave this example in another comment: Lets say I have a cookie, and there are 10 kids in front of me who like cookies. If I give any kid a cookie for any reason, it doesn't HARM the kids who don't get a cookie; they are no better or worse off than if the cookie never existed. However, suppose I decide to give the cookie to the tallest kid - even though none of the other kids are harmed, this is still not a 'fair' situation. You can do no harm and still be unfair. Whether that is bad or not is subjective, but it is still unfair (in the sense that every kid has an equal chance at the cookie). Of course, whether being absolutely fair is worth foregoing pareto-superiour improvements is a moral argument, and there is no objectivly correct answer to that.
    - Sniffnoy 9y ago
      I'm afraid the beginning of your comment contradicts your earlier statements. Earlier you agreed that in that restricted situation, it is in fact a Pareto improvement. However, now you are saying it is a zero-sum game. There are no Pareto improvements in a zero-sum game! The rest of your comment just returns to the claim that the whole thing is unfair even though nobody is harmed. But that's not the part I'm claiming is wrong! The part I'm pointing out as a "straight-up error" is the part where it denies that (in the restricted context of a single year where people didn't know that trading would be possible) is indeed a Pareto-improvement. I'm not making any argument as to the broader fairness. I'm not sure we really disagree on much here.
      - cortesoft 9y ago
        Fair enough, I should probably have said 'seemingly pareto-superior' or 'pareto-superior depending on your definition of fairness'.
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- wolco 9y ago
  Not sure I understand. If I want to go to the 10th best place why would I attempt to get #1 in the hopes of trading for #10. My odds are better if I apply to #10
- emn13 9y ago
  Note that even if everyone were equally able to strategize, doing so would reduce efficiency: after all, to strategize students lie about their preferences, and the lottery takes those lies into account. It's the garbage in; garbage out principle. Some of the stratgizing students will get into schools on their list they really only put there as a trading option. So it's not just about fairness; it's also about ensuring the algorithm works in the first place.
gpvos 9y ago
But other students are affected, namely next year's (and later) students, and especially those who are not so good at strategy. You must consider them too to evaluate the fairness of the rule.
- bonesss 9y ago
  And missing from all the analysis I've seen so far: some nations have baked "equality" into their approach to legal decisions. The trading policy was deemed discriminatory, enhancing some students at the "expense" of others. "At the expense of" means "so as to cause harm to or neglect of". The other students were not directly denied something, and did not lose their spots in school. What they would have lost, had the swapping been permitted, is an equal and fair treatment by their government and laws while being placed in school. As swapping allows some "haves", thereby also creating "have nots", the government deemed that to be enhancing some "at the expense of" others who were denied equal opportunity and treatment under the law. They lost fairness, equality, and "freedom" (in American parlance). I mean... "Whites only bathrooms come at the expense of civil liberties." is not a controversial assertion. The judge ruled that everyone not being equal causes harm/neglect. ESL author Ronald de Haan was using the word and phrase correctly, I think it is being misapplied in most of this discussion by a degree of pedantic over-parsing.
Confiks 9y ago
I would say you are arguing against quite a contrived point. The article speaks about the methodologies for holding fair lotteries in the context of doing this year after year. You are technically correct that allowing trading once wouldn't harm other students, but that is quite beside the point. The judge made this decision primarily on the basis that subsequent lotteries have to be held.
- bonesss 9y ago
  > You are technically correct that allowing trading once wouldn't harm other students, but that is quite beside the point. The judge made this decision primarily on the basis that subsequent lotteries have to be held. I gotta disagree: Harm in this case is not the distinct action of losing a spot in school. Harm, as ruled by a judge in accordance with their legal system, is the unequal handling and unequal distribution of opportunity to a legally mandated, tax-funded, government service. The judge ruled the swapping unfair as it is _discriminatory_. The ESL author used a (highly appropriate!), term that's being parsed to death here based on a north american civil perspective. Had we seen this ruling in the states we would say the swapping was "unconstitutional under the equal protections clause". Because making some people more equal some of the time makes the rest of us less equal all of the time. The winners are enhanced at our collective expense.

deleted 9y ago

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cortesoft 9y ago

You are missing some key points - if they allow trading, they are going to incentivize people choosing popular schools instead of ones they actually want to go to. Since more people are going to choose popular schools in hopes of getting a good trading asset, people who ACTUALLY want to go to those popular schools are going to be less likely to get in. Your assertion that it is an 'error' is only true if they only allow the trading to happen this year (after the preferences were set), and not in future years. The trades are only pareto-superiour if there are no future decisions to be made; since this is a repeated game, allowing pareto-superior trades this year means that next years game will NOT be fair (by their definition of fairness). I agree that their definition of 'fairness' is not objective, but it is one they have decided to go with; they decided that the ability to strategize is not evenly distributed, and so allowing strategy is unfair.

Sniffnoy 9y ago
Yes, the incentives this sets up could be bad for subsequent rounds; that is absolutely a real problem, as I mentioned. But this passage seemed to be suggesting that trading, in and of itself, harmed students who were not involved in the trade, and that's not correct. Notice it explicitly says: > This would give them better chances. At the expense of students that don’t (or can’t) trade. But in fact those students are unaffected. In subsequent years, as you say, it is a problem. But I don't see how to read that part as anything other than denying that when just restricted to that year it is a Pareto-improvement. You may say "well that's a self-evidently stupid claim; of course they're not making that claim, because that would be stupid". But there's a lot of people out there who really seem to believe in a zero-sum world, and are convinced that when anyone's position improves, that means that everyone else has been harmed. That Pareto improvements are fundamentally impossible. There are absolutely people out there who would make that claim.
- cortesoft 9y ago
  This IS a zero sum game, though. There are only x number of spots at each school. I agree that the wording of 'at the expense of' is a bit misleading, but I don't think it is categorically incorrect. The idea of fairness can, by certain definitions, even encompass pareto-superiour situation, if the improvements are not distributed fairly. I gave this example in another comment: Lets say I have a cookie, and there are 10 kids in front of me who like cookies. If I give any kid a cookie for any reason, it doesn't HARM the kids who don't get a cookie; they are no better or worse off than if the cookie never existed. However, suppose I decide to give the cookie to the tallest kid - even though none of the other kids are harmed, this is still not a 'fair' situation. You can do no harm and still be unfair. Whether that is bad or not is subjective, but it is still unfair (in the sense that every kid has an equal chance at the cookie). Of course, whether being absolutely fair is worth foregoing pareto-superiour improvements is a moral argument, and there is no objectivly correct answer to that.
  - Sniffnoy 9y ago
    I'm afraid the beginning of your comment contradicts your earlier statements. Earlier you agreed that in that restricted situation, it is in fact a Pareto improvement. However, now you are saying it is a zero-sum game. There are no Pareto improvements in a zero-sum game! The rest of your comment just returns to the claim that the whole thing is unfair even though nobody is harmed. But that's not the part I'm claiming is wrong! The part I'm pointing out as a "straight-up error" is the part where it denies that (in the restricted context of a single year where people didn't know that trading would be possible) is indeed a Pareto-improvement. I'm not making any argument as to the broader fairness. I'm not sure we really disagree on much here.
    - cortesoft 9y ago
      Fair enough, I should probably have said 'seemingly pareto-superior' or 'pareto-superior depending on your definition of fairness'.
- deleted 9y ago
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wolco 9y ago
Not sure I understand. If I want to go to the 10th best place why would I attempt to get #1 in the hopes of trading for #10. My odds are better if I apply to #10
emn13 9y ago
Note that even if everyone were equally able to strategize, doing so would reduce efficiency: after all, to strategize students lie about their preferences, and the lottery takes those lies into account. It's the garbage in; garbage out principle. Some of the stratgizing students will get into schools on their list they really only put there as a trading option. So it's not just about fairness; it's also about ensuring the algorithm works in the first place.

gpvos 9y ago

But other students are affected, namely next year's (and later) students, and especially those who are not so good at strategy. You must consider them too to evaluate the fairness of the rule.

bonesss 9y ago
And missing from all the analysis I've seen so far: some nations have baked "equality" into their approach to legal decisions. The trading policy was deemed discriminatory, enhancing some students at the "expense" of others. "At the expense of" means "so as to cause harm to or neglect of". The other students were not directly denied something, and did not lose their spots in school. What they would have lost, had the swapping been permitted, is an equal and fair treatment by their government and laws while being placed in school. As swapping allows some "haves", thereby also creating "have nots", the government deemed that to be enhancing some "at the expense of" others who were denied equal opportunity and treatment under the law. They lost fairness, equality, and "freedom" (in American parlance). I mean... "Whites only bathrooms come at the expense of civil liberties." is not a controversial assertion. The judge ruled that everyone not being equal causes harm/neglect. ESL author Ronald de Haan was using the word and phrase correctly, I think it is being misapplied in most of this discussion by a degree of pedantic over-parsing.

Confiks 9y ago

I would say you are arguing against quite a contrived point. The article speaks about the methodologies for holding fair lotteries in the context of doing this year after year. You are technically correct that allowing trading once wouldn't harm other students, but that is quite beside the point. The judge made this decision primarily on the basis that subsequent lotteries have to be held.

bonesss 9y ago
> You are technically correct that allowing trading once wouldn't harm other students, but that is quite beside the point. The judge made this decision primarily on the basis that subsequent lotteries have to be held. I gotta disagree: Harm in this case is not the distinct action of losing a spot in school. Harm, as ruled by a judge in accordance with their legal system, is the unequal handling and unequal distribution of opportunity to a legally mandated, tax-funded, government service. The judge ruled the swapping unfair as it is _discriminatory_. The ESL author used a (highly appropriate!), term that's being parsed to death here based on a north american civil perspective. Had we seen this ruling in the states we would say the swapping was "unconstitutional under the equal protections clause". Because making some people more equal some of the time makes the rest of us less equal all of the time. The winners are enhanced at our collective expense.