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Divide Your Rent Fairly
- danso 13y agoThis app did not make much sense to me because I was sitting at my computer making choices for myself and my non-present roommate. So the related article with useful visual explanation of Sperner's Lemma may be more useful reading if you don't have a quorum of your roommates to work with this morning: http://www.nytimes.com/2014/04/29/science/to-divide-the-rent-start-with-a-triangle.html http://www.nytimes.com/2014/04/29/science/to-divide-the-rent...
- Anderkent 13y agoSperner's Lemma is cool, but since it can be gamed and your preferences will change anyway (so the envy-freeness is only temporary) it's more of a curiosity than a true solution.
- coob 13y agoDoes this still work if one person has an upper limit on how much they can spend that is less than an equal split?
- cowsandmilk 13y agoyes... unless the conclusion from the process is that the apartment is too expensive for the roommates to split; or your preferences are not compatible with each other.
- ronaldx 13y agoThe algorithm is likely to ask anyone to choose a favoured room from an equal split, so in theory the algorithm won't work if someone has a smaller-than-equality budget. The algorithm depends on everyone having a personal way of splitting the cost of the house so that they would be equally happy with any room. If you are only willing to spend less-than-equality on a particular room, you should be prepared to spend more-than-equality on another room to compensate. Someone without that possibility might get a result incompatible with their needs or might be taken advantage of by a knowledgeable enemy player, I would think. So in theory, no, this method won't work perfectly. But in practice, yes, you might still get a decent result. This algorithm is good for cake-cutting, since everyone likes to receive cake, but less good for rent-splitting, since not everyone likes to pay rent.
- sesqu 13y agoIt might. The associated paper makes the assumption that for every division of rent, some room is acceptable. However, the lemma itself makes no such demand, but only guarantees the existence of an approximate rent division. The algorithm given refines the rent division iteratively, so an upper spend limit only means you might end up with rooms assigned and a portion of the rent unpaid. You could then fix the underfunded tenant's room and iterate on the others, but there's no longer a guarantee that the others wouldn't envy the bum's rent.
- oleganza 13y agoReminds me of an old puzzle: how to split bread in two parts so no one is upset? Alice splits, Bob chooses the one he wants. If both prefer at least half, Alice will try hard to split as close to 50/50 as possible and, most importantly, no one will feel bad because everyone had his say.
- cschmidt 13y agoYes, these are a generalization of "I split, you choose" to more general cases. It is a way of getting an envy-free distribution. It is often called the cake cutting problem. There are some interesting books on the topic... http://www.amazon.com/Cake-Cutting-Algorithms-Fair-You-Can/dp/1568810768 http://www.amazon.com/Cake-Cutting-Algorithms-Fair-You-Can/d...
- arethuza 13y agoAlso "Shotgun clauses" in shareholder agreements - which try and create a last resort mechanism for fairly agreeing on a share price: http://en.wikipedia.org/wiki/Shotgun_clause http://en.wikipedia.org/wiki/Shotgun_clause
- oneeyedpigeon 13y agoI always propose this method, but also suggest that the other person does the dividing :)
- watwut 13y agoI want to be the one who chooses. It is humanly impossible to split the bread to two exact parts. Choosing which part is bigger is easy in most cases.
- mturmon 13y agoToss a fair coin to see who cuts and who chooses.
- nobotty 13y agoBoo. That registration gate can go right away.
- viggity 13y agoclick on the search result link, it'll kill the register wall. https://www.google.com/search?q=divide+your+rent+fairly&oq=divide+your+rent+fairly https://www.google.com/search?q=divide+your+rent+fairly&oq=d...
- akilism 13y agoby far the easiest way around the nyt paywall is to just open the link in an incognito window.
- joshstrange 13y agoIf you often split the bill on anything Rent/Utilities/Drinks/etc you should check out Splitwise [0]. They have a Web/iOS/Android apps and it has been a life saver. I've used it for a little over a year now and it makes all expenses a breeze. It keeps track of who owes who what and can (when enabled) even simplify the debts so if person A owes $10 to person B and person B owes $10 to person C then Splitwise will report that person A owes person C $10. Note: I have no affiliation with Splitwise, I just love the product. [0] https://www.splitwise.com/ https://www.splitwise.com/
- mason55 13y agoI don't think this has anything to do with the article/calculator. The OP is about an auction process to determine who pays what, not actually exchanging the money or tracking it.
- mathattack 13y agoThis worked for me in the past. Once we settled on rooms, we bid for the largest ones. Very efficient. Still split utilities multiple ways. The only problem is in one situation when one of the guys moved his girlfriend in without asking.
- joshstrange 13y agoIt has to do with splitting the cost of shared resources, I will agree that it's not the same as the OP but I will argue that it is in the same vein and further more that people that are interested in how best to split rent might also be interested in a way to facilitate the collection and tracking of said rent. Edit: Also see Splitwise's rent calculator: https://www.splitwise.com/calculators/rent https://www.splitwise.com/calculators/rent
- pkfrank 13y agoAgreed, I think it's totally relevant and thanks for the Splitwise link. I've been waiting for Venmo to integrate roommate-inspired features for ages.
- viggity 13y agoThere is a register wall. if you search google for "divide your rent fairly", and click on it from the search results, it'll let you in. https://www.google.com/search?q=divide+your+rent+fairly&oq=divide+your+rent+fairly https://www.google.com/search?q=divide+your+rent+fairly&oq=d...
- Wilduck 13y agoAlternatively, visit the linked article directly in an incognito window.
- deleted 13y ago[deleted]
- kevinkimball 13y agoThat's not really similar at all.
- rbcgerard 13y agoFound this fairly annoying - only because I went through this exercise recently, and now all the research i did has been made redundant. I bought this book to help me out: http://www.amazon.com/Fair-Division-Cake-Cutting-Dispute-Resolution/dp/0521556449/ref=sr_1_1?ie=UTF8&qid=1398781523&sr=8-1&keywords=fair+division http://www.amazon.com/Fair-Division-Cake-Cutting-Dispute-Res... It's a great book, though it didn't include exactly what i was looking for regarding this subject. I emailed one of the authors and he kindly pointed me in the direction of Sperner's Lemma: http://www.inet.tu-berlin.de/fileadmin/fg234_tdc1-s11/FDS_SS_2012/Script/Sperner-rental.pdf http://www.inet.tu-berlin.de/fileadmin/fg234_tdc1-s11/FDS_SS... and I was able to find: http://www.math.hmc.edu/~su/fairdivision/calc/ http://www.math.hmc.edu/~su/fairdivision/calc/ Which is the same sort of calculator... Anyway same end result...though i highly recommend the book above if anyone is interested in the subject.
- Steuard 13y agoIn particular, the NYT's new calculator is a reimplementation of the calculator you found by Francis Su and his student(s) (which it cites).
- HUSSTECH 13y agoOf all the things to appear on HN! In a kind of joke response to a recent house search with a couple of friends, I made a site that splits the rent based on room size. Rough round the edges, but feel free to try it out. http://whogetsthesmallroom.com/ http://whogetsthesmallroom.com/
- alex-g 13y agoSperner's Lemma is probably my favorite mathematical result. It is easy to explain, and pretty easy to prove, but it has a higher than average number of "aha" moments along the way. The mathematics is not too intimidating - probably the scariest thing is the generalization to n dimensions, which requires induction. It is also fun to explain the connections to Nash's theorem and so on, as invoked in this article.
- npongratz 13y agoMy favorite introduction to the subject of fair division was Ian Stewart's "Your Half's Bigger Than My Half!", Scientific American, December 1998: http://www.whydomath.org/Reading_Room_Material/ian_stewart/yourhalf.html http://www.whydomath.org/Reading_Room_Material/ian_stewart/y... It's an interesting, accessible, practical application of mathematics and logic. Fun for the whole family!
- MCarusi 13y agoThis is probably going to be helpful for people who can't afford to pay 1-2 months of rent due to not having a job, so they can calculate what they'll owe down the road. I've seen situations where one person is "temporarily" handling the lion's share of the rent, and as that temporary situation becomes indefinite, resentment starts boiling.
- JosephBrown 13y agoNow can we figure out a way to split expenses like cable (some may not want it), lawn services (how frequent), etc?
- baking 13y agoThis seems buggy to me, but I'm not familiar with the algorithm. In my test case, neither roommate agreed to pay more than $562.50 for room 1, but the result was that roommate A had to pay $578.13 so it seems kind of arbitrary. Edit: Never mind, I didn't notice that it allowed me to continue.
- YokoZar 13y agoAlso note that it provides error bars around the result -- in your case 578.13 minus those error bars was probably less than 562.50.
- SyncTheory13 13y agoI've lived with tons of roommates the last 5 years and do not see the utility in this... There are jut too many factors to take into consideration. We are currently in a 4-bedroom house with other amenities. Two of the bedrooms are very small, and two are large. First, each room starts at a base amount to take into consideration the shared spaces... Which is $50 for us. So... $700/mo. total - $200/mo. for all 4 rooms = $500/mo. leftover. Then we split the rooms into amounts that we agreed seem fair based on the sizes. As a median, $500/4 = $125. The large rooms are $165, small rooms are $85. Add in the $50 from before and we have: Large Room: $215 Large Room: $215 Small Room: $135 Small Room: $135 Basically, you're paying a base price for the shared space, then an additional price for the approximate square footage of your room. We avoid going into exact measurements to keep it simple. As far as utilities go, it was a nightmare to organize them every month and collect what everybody owed, especially when people started owing over a couple months past. Making sure to record payments, update the balances, ask for payments, pay all the bills, and sometimes organize which bills get paid first because we owed was a disaster. So, for utilities, I calculated the yearly average of all of them divided by the minimum number of roommates (4 in our case), added ~10-15% on the top, and that was our new monthly utility bill. Everybody pays the same amount every month. Rent is due on the 1st. Utilities are due on the 15th. I track payments using Google Docs so they have access. Also annoying was the process in which people bought supplies for the house and wanting reimbursements... Sometimes people would buy the same things and we'd have a stock of them, etc... So that extra cushion in the utilities goes toward purchasing house supplies in bulk. All of the money goes into a PayPal student account with a debit card. Everybody has access to Mint.com to see transactions/balance, but only I have access to the actual account. Anybody can use the debit card, and I get text/email alerts for every transaction. If we end up having a large balance, we can improve something in the shared spaces or repay debts from roommates that had to be kicked out for owing (face it... that money is gone - Always collect a security deposit!). We believe this system is fair and scaleable, as it rewards people for sharing rooms rather than making them pay more for the same space... But as the number of people grows, the cushion in the utilities grows to a larger percentage... Making it possible to improve our shared space living conditions as a reward for putting up with too many roommates. For instance, supplying everything we need for a full garden in the back yard, etc. I apologize for this long-winded explanation, but I hope this helps somebody. Compared to the way of normally splitting up a house, this is much simpler. Everybody knows what they pay in rent for their room, they know how much they'd pay if they moved their partner in, they know how much utilities are, and everything is transparent. The main thing I haven't figured out is chores/shared duties outside of just cleaning up after yourself. We have a whole 100+ year-old house to maintain/rehab, and there is a lot to do. Working on some kind of system where people can choose from a revolving list what chores they want to do to accumulate their points. First come, first choice. HabitRPG looks promising in that you can get groups together and tasks go up in value the longer they aren't done. Also, having repercussions for late-payments/lack of chores. We're not big on charging interest/fines to those that cannot afford it already... But will soon be experimenting with taking away access to house amenities... For instance, the upstairs (nicer) bathroom, the high-speed Internet, our shared access to the local Hackerspace, etc.
- deleted 13y ago[deleted]
- twic 13y agoI think the two people just act as a tiny corporation in the bidding process, and enter a single set of bids, just like the single people. Equally, if one person wanted two rooms, they would enter two sets of bids. I further think that this could easily end up putting everyone in the same rooms, at the same prices. In terms of paying for the bedrooms, this seems fair. Yes, the couple are each paying half as much for the room as when it had a single occupant. But they're also only getting half the use of the room, because they're sharing it. In terms of paying for the shared spaces, this does seem less fair, because everyone else now has a slightly smaller share of the use of those, whereas the couple jointly has two of those slightly smaller shares. I think the way that this ultimately shakes out is that the other housemates might decide that none of the room choices offer value for money, and move out of the house.
- twic 13y agoYou know what, forget this marriage stuff, people who REALLY love each other should just incorporate together. People blabber on about two hearts beating as one, but by incorporating, they'd be LEGALLY a single person! Plus, the veil on a wedding dress is just a piece of gauze, but the one on a corporation is protected by a thick layer of case law. And just think of all the beautiful honeymoon locations in Delaware!
- bendauphinee 13y agoMyself and my g/f moved into a house with 2 friends. We figured a fair way to divide the rent and expenses. We measured out the sqft of the bedrooms, and used the percentages of each room from the total bedroom sqft to split the rent and any fixed expenses like internet and lawn care (since those costs don't change based on per person usage). We applied the same to cleaning supplies and things like light bulbs in common spaces. (Chosen Bedroom SQFT / Total Bedroom SQFT = Chosen Bedroom Expense %) For power, since that can vary month to month based on usage, we split it by the number of people in the house. This month, one of the friends is moving out and we're taking her room over as an office, so the power split changes to 3 way instead of 4 way, but the other friend won't see a change in her other expenses because her percentage of the bedrooms floor space is still the same. Easy on math and easy to manage. All expenses are tracked in a Google Doc shared to all of us, and at the end of each month I run the numbers to calculate who pays what to who to balance it out.
- dntrkv 13y agoThat's a good start but it doesn't account for bedrooms that are better. For example, one bedroom may have a huge bay window with a nice view and the other has a tiny alley alley facing window. How do you count that into the cost?
- TillE 13y agoGenerally you don't. First come, first serve. If you're not willing to pay the area-proportional price of the room, someone else will be. The only situation where this would be relevant is if you're a group of friends all looking for a new apartment together. After university, that's pretty unusual.
- skwirl 13y agoYou're saying that if a unit has two 500 square foot bedrooms, and one is in the basement with no windows next to the furnace and the other is upstairs with bay windows on two walls facing a garden, there is always someone willing to pay half of the overall rent for the basement unit? How exactly are you arriving at this extremely counter intuitive conclusion?
- ttty 13y agoQuite fair: http://www.nytimes.com/interactive/2014/science/rent-division-calculator.html?_r=1#2|100|A|Roommate%20A|B|Roommate%20B|1|Room%201|2|Room%202|1221111221212 http://www.nytimes.com/interactive/2014/science/rent-divisio... $98.44 and $1.56 xD
- TheCoelacanth 13y agoYour example would indicate that both roommates had a strong preference for room A over room B, so in that sense it is fair for the person getting room A to pay more.
- tammer 13y agoInteresting that almost all the comments thus far are regarding the actual content of the article and intention of the page rather than the relative novelty page itself. I think that alone is evidence that the Times has hit its stride as a 21st century news outlet.
- balls187 13y agoFair is an interesting concept. How do you set the rent? If it's an apartment, it's the fixed cost set by the landlord, but what if you are the landlord? Do you set the rent to be based on the mortgage, or based on rents for similar properties? With that same logic, if you had a place that was below market, could you set rent to market and charge that?
- ihaveqvestion 13y agoCan someone explain why the outcomes differ when the roommates are in a different order? Imagine an apartment with one nice room and one terrible room, total rent $1000, and two roommates, one rich, one poor. The poor roommate will always chose the less expensive room, the rich roommate will always chose the nice room unless the price difference is greater than $500. If the rich roommate is Roommate A, then it converges to a 50/50 split, each paying $500. If the rich roommate is Roommate B, it converges to a 75/25 split, with the rich roommate paying $750. What's going on there? [EDIT: Also, I've just discovered with three roommates that the results may be displayed without the first roommate ever choosing at all. ???]
- ihaveqvestion 13y agoI think the key may be that the rich roommate actually prefers a room, while the poor roommate does not (according to their assigned valuations) have any room preference at all. So if the poor roommate is second, they make the most choices in this calculator and their lack of preference makes the split even, whereas if the rich roommate is second, they make the most choices and their stronger preference causes them to pay more. Even so, the order still seems to matter somewhat, and I would have expected it not to matter at all.
- yuliyp 13y agoIt doesn't guarantee a perfect allocation, but one that is compatible with everyone's preferences. A is willing to pay up to $750 for the nice room and up to $250 for the bad room. B is willing to pay up to $500 for either room. Any solution where A takes the expensive room for $500-$750 and B takes the cheap room for $250-$500 will leave both content with their choice. B could do better by being strategic and switching his preference to only taking the cheap room for no more than $300, however.
- ihaveqvestion 13y agoThanks, I think that's what I was misunderstanding.
- kennywinker 13y ago"Fair" in the good old American capitalist sense of the word. Money is supposed to be a proxy for desire here... The one that desires the room more gets it because they are willing to pay more for it. The reality is money isn't an equal proxy for desire. The poorer roomate can want the big room with every fibre of their being, but be casually outbid by a rich roommate with money to burn. Edit: as expected, HN swings decidedly capitalistic and my comment has been downvoted.
- sp332 13y agoSo if you get the room you really want, why should another person get stuck paying more for a worse room? You might say that the landlord should just give the apartment to the people who want it the most, and only charge what they can afford to pay him. But the landlord isn't looking to maximize desire, he's looking for the most money. So really, the reason the solution is to give more desirable things to people with more money, is that the owner of the desirable thing is looking to maximize money, not just match desire of the apartment with desire of your money. So he's trying to take the most money the rich person is willing to give and the most money the poorer person is willing to give.
- kennywinker 13y agoIn practice it's usually the tenants picking the rent split, not the landlord. Two friends move in, they agree that they'll split the rent roughly equally, but maybe the bigger room is worth an extra $50 or something. Often they'll just split the rent equally despite an obvious difference in objective quality between the rooms. This is because when it comes to family and friends, we often behave in anti-capitalist ways. This is why the idea of capitalism seems "cold" and "uncaring", because when it comes to those close to us we don't act strictly capitalistically.
- sp332 13y agoSure they decide among themselves what the split is. But I mean, if the richer person is willing to pay $750 for the better room and the poorer person is willing to pay up to $500 for either room, the best move for the landlord is to raise the rent overall!
- esquivalience 13y agoThis is quite a claim. I find the difficulty with "fair" is that it means different things to different people.
- esquivalience 13y agoThis is quite a claim. I find the difficulty with "fair" is that it means different things to different people.
- esquivalience 13y agoThis is quite a claim. I find the difficulty with "fair" is that it means different things to different people.
- esquivalience 13y agoThis is quite a claim. I find the difficulty with "fair" is that it means different things to different people.
- esquivalience 13y agoThis is quite a claim. I find the difficulty with "fair" is that it means different things to different people.
- esquivalience 13y agoThis is quite a claim. I find the difficulty with "fair" is that it means different things to different people.
- dyeje 13y agoI have never heard of this system. Rent has always been (total rent / number of roommates). This seems a bit overly complex.
- TTPrograms 13y agoPeople value different rooms differently. Auctions are usually good solutions to this. Idea: 1) Each roommate secretly prices how much they would pay for each room. 2) The highest payment proposed is allocated the selected room. The payments are gone down in decreasing value until everyone is assigned a room. 3) Rent is divided among the renters in amount proportional to the bids accepted.
- likeclockwork 13y agoWhy not just divide the total rent by the total square footage to get a rate for the space and then have each person pay for their private space plus a their share of the common space?
- thom 13y agoSperner's lemma feels very much like eBay's proxy bidding - you put the maximum you're willing to pay in, and eBay will bid up to that value and not over. And then with ten minutes left, you go back to the auction and start desperately typing in higher and higher numbers because you have to have teh shiny, rationality be damned.