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Suspicious Discontinuities

644 points by janvdberg 7y ago

smoyer 7y ago
The youth sports discontinuity was a problem for me when I became old enough to play little league, but was exploited by me when I should have moved on to Teener League. I was born on the cut-off date for Little League, so I was the youngest player on the team my first year (and the youngest for my grade the other years.) Do to ambiguity in how the cut-off date wording was written, I ended up (legally) playing a fourth year when I was 13. I was never a big kid but at this point I was certainly bigger than all the 10 year-olds and more importantly had gained coordination and experience. It was my favorite year playing baseball. (As an aside, I paid karma for it the next year ... I spent eighth grade in a city Teener League where I was once again the smallest, least experienced kid. And the city league was way more cut-throat than what I'd experienced in the suburban setting my previous four years.)
- eloff 7y ago
  I was always small until about age 16, and I always sucked at sports and never really got into them - partly as a result. I wonder if we shouldn't group kids by size for sporting activities instead of by age. There's a famous statistic in Canada that NHL players are much more likely to be born in January and February than September-December. The reason being is they were nearly a year older than other kids they were paired with, so they did better at the sport and thus kept it up as they grew. Seems silly.
  - EpicEng 7y ago
    >I wonder if we shouldn't group kids by size for sporting activities instead of by age. Depending on how small your buckets are, you may end up with a scarcity problem (players and admins/coaches). Also, age matters a lot in regards to coordination. A 13 year old who is roughly the size as a ten year old will, on average, have a large advantage. Some people just aren't cut out for athletics genetically. Some grow later on and may or may not be interested. Age seems like a fair sorting criteria and general enough to not introduce too much complexity.
    - joombaga 7y ago
      > A 13 year old who is roughly the size as a ten year old will, on average, have a large advantage. This is an interesting claim. How much is a large advantage? Do you mean in hockey specifically? Or in athletics? Or any given task?
    - bradlys 7y ago
      > Some people just aren't cut out for athletics genetically. Some grow later on and may or may not be interested. Age seems like a fair sorting criteria and general enough to not introduce too much complexity. Age isn't particularly fair but it isn't the worst either. As a kid, being around kids younger than you can be really displeasing. When you're a kid, the only thing you want is to be treated like you're older/better than you are. If you keep getting put on teams for people who are small - it's likely you're being put on teams for people who are smaller than you. I had to play baseball with 7-yr olds for about 3 years. It wore me down as a kid. I gave up on baseball at that point and said I wasn't doing it anymore. The reason I had to play with them is because no coach wanted me on their team because they saw me as too small. (Small town, they didn't group by age as much as they did by size) I'd see kids go up to bigger-kid teams and get bigger but I stayed the same size. As a kid - it was super disheartening to be stuck with the same 7 to 8 year olds for all that time and seeing people you used to play with in the bigger kid league. It sucked. That said - baseball is probably the ONLY sport I can imagine being where you could move kids up by age and not by size as much. Football, soccer, basketball, etc. all involve a serious size component to them whereas baseball is less so - in my mind. For reference - I grew up to be a normal sized adult. I was just super late on the curve compared to my peers.
      - SamReidHughes 7y ago
        When I was a kid, our club soccer travel team of 4th graders beat an intramural team of 6th graders by 3 goals. Our coach lost $100, because he'd bet we'd win by at least 4. I think soccer and basketball much moreso involve a coordination and fitness component than size. In youth soccer, you have to outrun the other kids and handle the ball well. Messi is 5'7". In basketball, of course, height does help a lot there, but amongst local kids, better to be able to make shots, dribble, and get around the court. Football was the only sport that segregated by size in my school system's leagues, in middle school. Well, besides wrestling, of course. They're contact sports.
  - alexis_fr 7y ago
    > The reason being is they were nearly a year older than other kids they were paired with. I’m amused that the kids who did worse are absolutely necessary for the kids who do better. They end up getting wasted by the process, demotivated, but they are a necessary brick to step upon. It’s the same consideration when talking about male suicide. Are they necessary for others to feel good? We could solve a good part of it as a society, but at the expense of providing an environment where males fail less, have a better social net, receive more love, and are less pushed to succeed in their career to be recognized. So we could solve it, but it may cost our economic growth. Is that why male suicide isn’t getting solved? It’s getting less funding than even dog shelters, and less attention than much smaller problems.
    - nl 7y ago
      It’s the same consideration when talking about male suicide. Are they necessary for others to feel good? No. There's no evidence at all to support this view. In fact there is evidence to support the view that people who feel good when others feel bad are more likely to have suicidal tendencies.
      - alexis_fr 7y ago
        Then... why don’t we act against it? Isn’t it, then, more urgent than other topics? It doesn’t seem like we care, given we always treat male complaints as crybabies.
  - jmmcd 7y ago
    > I wonder if we shouldn't group kids by size for sporting activities instead of by age. This is how it's done in rugby in New Zealand and maybe a few other countries, but not most. It's much more important in rugby than in baseball!
- habosa 7y ago
  I had the exact same experience. I was one of the youngest people in my year and one of the worst players on my team. Until my age 13 season, when they wouldn't let me move up into the teenager league because of a one=month difference in age. So I was pitching to kids who had just turned 10 ... I threw a lot of strikeouts that year and hit my only home run ever haha.
leto_ii 7y ago
The Economist recently had some more detailed plots on the crack cocaine discontinuities: https://www.economist.com/graphic-detail/2020/01/18/smoking-gun-evidence-emerges-for-racial-bias-in-american-courts https://www.economist.com/graphic-detail/2020/01/18/smoking-...
cs702 7y ago
Any rules that can be gamed, sooner or later, inevitably, will be gamed. The "suspicious discontinuities" shown in this fantastic post are evidence for it. It seems to be an Iron Law of Human Nature.
- hn_throwaway_99 7y ago
  This 'Iron Law of Human Nature' is a corollary of Goodhart's Law: https://en.wikipedia.org/wiki/Goodhart%27s_law https://en.wikipedia.org/wiki/Goodhart%27s_law
- ChainOfFools 7y ago
  what gets measured gets treasured
throwaway023421 7y ago
The statistics on the amount of cocaine show an appalling pattern of lying and false evidence from the police. It's even more appalling that people hardly acknowledge such bias.
- lolc 7y ago
  Please do not jump to conclusions and read the footnote which addresses that point explicitly: "drug seizure records, amounts seized do not appear to be the cause of this change."
  - mjw1007 7y ago
    That seems to mean "if you assume that the drug seizure records are not falsified, you can conclude that the police are not lying or producing false evidence".
    - ls612 7y ago
      It means the police are not falsifying records of drug seizures to make them hit any of the statutory thresholds. They may be falsifying them in other ways but this can’t be verified one way or another by this data.
  - tqi 7y ago
    I do not have access to the original paper, but author's assessment that the bunching is due to prosecutorial discretion is a little puzzling to me. If it is true that prosecutors are choosing to prosecute cases that are above the cutoff at a higher rate than those below, I would have expected everything above 280g to increase, rather than a solitary spike at 280g?
    - wahern 7y ago
      From Note 1: > prosecutors can charge people for amounts that are not the same as the amount seized and then notes If someone is caught with 500g you can simply charge 280g and make your life easier. If you charge 500g the defendant will argue it was just 450g, which even if irrelevant makes the case seem weaker to the jury--death by a thousand cuts. But if you charge 280g and present evidence of 500g, it makes the case seem more like a slam-dunk to the jury.
ceejayoz 7y ago
> One reason people were looking for ways to lose money was that, in the U.S., there's a hard income cutoff for a health insurance subsidy at $48,560 for individuals (higher for larger households; $100,400 for a family of four). There are a number of factors that can cause the details to vary (age, location, household size, type of plan), but across all circumstances, it wouldn't have been uncommon for an individual going from one side of the cut-off to the other to have their health insurance cost increase by roughly $7200/yr. That means if an individual buying ACA insurance was going to earn $55k, they'd be better off reducing their income by $6440 and getting under the $48,560 subsidy ceiling than they are earning $55k. This is an incredibly dumb way to structure things.
- hammock 7y ago
  https://en.wikipedia.org/wiki/Welfare_trap https://en.wikipedia.org/wiki/Welfare_trap
- thundergolfer 7y ago
  Too many smart people in the US are working to invent things like the 'Double Irish with a Dutch Sandwich'[1] rather than fixings these massive equity and fairness problems at the bottom end. 1. https://www.investopedia.com/terms/d/double-irish-with-a-dutch-sandwich.asp https://www.investopedia.com/terms/d/double-irish-with-a-dut...
  - deleted 7y ago
    [deleted]
- quickthrowman 7y ago
  There are 0 Congresspeople that are near the threshold, which could be related.. Congress seems to focus on ensuring wealthy citizens and corporations gain more wealth, and not making things fair for everyone else.
- myself248 7y ago
  What's eye-opening is the author's point about _how_ many people go about ditching some income at the last minute -- by buying a particular type of financial product whose value is likely to go to zero. Which has the effect of transferring their wealth to someone else (the vendor of the financial product) who just sold something that was effectively worth nothing, for a great deal of money. It's the most bizarre sort of wealth redistribution I've ever heard of.
ww520 7y ago
IRS would do well catching tax evasion by running some statistic models to find suspicious discontinuities.
- jacques_chester 7y ago
  They do. Tax agencies worldwide have used statistical techniques for decades.
  - TeMPOraL 7y ago
    Benford's law is probably the most known example. https://en.wikipedia.org/wiki/Benford%27s_law https://en.wikipedia.org/wiki/Benford%27s_law
lkbm 7y ago
OKCupid has a graph of reported height for men[0]. It's both shifted 2 inches to the right of average, but also slightly flattened at the normal peak of 5'10". It's not nearly as pronounced as the graphs in this post, but it's still notable. [0] https://theblog.okcupid.com/the-big-lies-people-tell-in-online-dating-a9e3990d6ae2 https://theblog.okcupid.com/the-big-lies-people-tell-in-onli...
- hammock 7y ago
  Both men and women showed height above the national average. As a result I am more inclined to believe that there is selection bias in OKCupid audience (more white people, less minorities) than that there is such widespread deception going on.
  - birdyrooster 7y ago
    Exactly. Not to mention short people may have opted out of dating because they lack a perceived fitness for dating.
    - gowld 7y ago
      Or tall people opt out of OKCupid because they can date offline.
      - birdyrooster 7y ago
        Or since it's so easy for tall people to date offline, they choose OKCupid because it's even easier due to the asynchronous model and network effect. They get more out of the algorithms than shorter people since more people are attracted to them.
    - deleted 7y ago
      [deleted]
  - opportune 7y ago
    Or it’s self reported and on average people fibbed up their height a smidge
maxmcd 7y ago
People playing speed chess (presumably) get fixated on improving their Elo rating by the next 100 point span, leading to spikes every 100 rating points in the distribution: https://lichess.org/stat/rating/distribution/bullet https://lichess.org/stat/rating/distribution/bullet
selimthegrim 7y ago
How about the US killing like 10 “Al Qaeda No 2”s in a row for a while in Iraq
- mumblemumble 7y ago
  If you order your hit list right, you can kill a continuous streak of #2s, until there's only one person left.
  - kevin_thibedeau 7y ago
    With only a few 100k casualties in collateral damage.
    - banads 7y ago
      And twice as many more potential #2s spring up as a result
- refurb 7y ago
  How is that weird? #2 gets killed, new #2 takes his/her place, #2 gets killed.
  - selimthegrim 7y ago
    Do you really think they were all actually No 2s? That AQI had that bad opsec? Don't we hit the No 3 too every once in a while?
    - refurb 7y ago
      Presumably the #3 became the #2, when the original #2 was killed. I see your point - do they just say #2 to sound impressive, however, they seem to know the structure of AQI pretty well and folks get promoted into that role when a death occurs, so I’m going with “likely true”.
aeturnum 7y ago
This is a lovely post and good general demonstration on this phenomenon. The drug charging graph is particularly stark. I think the most interesting graph is the final one, for marathon finishing times. The idea that people will fudge numbers to meet (or avoid) official definitions is commonly believed (and shown repeatedly here). It's more interesting to observe that it's not just people using motivated reasoning, but also that people will alter their performance to hit highly visible targets.
- Wehrdo 7y ago
  I think another factor for the marathon finishing time discontinuities is the use of pacers --- people who run carrying signs at a pre-defined speed (usually targeting a specific finishing time, e.g. 3:15). Lots of people who have finishing goals will run in a pack with this person so they know they're going fast enough, then will all finish just under the target time.
stared 7y ago
Ad Polish end of high school exams: quite a few years ago I created an interactive widget to explore it https://github.com/stared/delab-matury https://github.com/stared/delab-matury. There are a few jokes about the Matural Distribution (Matura is the name of this exam) or the Polish Gaussian. It is the Polish language, which is the most discontinuous. However: - There are quite a few scores for the essay which are subjective (e.g. on the style). - It is an official procedure that in the case of results on the edge, the person marking should mark an ambiguous score in the favour of the student.
- ehnto 7y ago
  > It is an official procedure that in the case of results on the edge, the person marking should mark an ambiguous score in the favour of the student Given that it's subjective, I find that a really generous and positive take on marking protocol. It takes some perspective to note that while you can't see the value in someone's work, there may still be value in it. edit: After reading through the article in full, I understand perhaps that's not what's going on exactly. Just teachers trying their hardest to find ways not to fail the exam as it is such an important life step for that person. Still a virtuous thing to do!
  - stared 7y ago
    I don't consider it virtuous! By pushing more to pass: - either the next year the problems will be more difficult, - or it devaluates the worth of passing an exam. Also, 30% is very low (especially as such cut-off are for the basic level exams, not advanced level exams). You get the high school diploma, but it is not something that is enough to get to any univ. that makes any sense (some will take such students, but only as they are being funded on the level of enrolment OR they are private and are essientially "a bribe-in rates for a diploma" style).
    - ehnto 7y ago
      Is it not a final exam for the entire schooling process? If it is, I don't think there's anything wrong with letting people who attended, tried and got close, a passing grade. As much as we value merit, the real world actually isn't a meritocracy, and high school isn't much of a measure for how successful someone has the potential to be. I think you begin to be right as people move into academia though, certainly you want people who are actually good at the subject to be the ones passing university and going into the work force.
deleted 7y ago
[deleted]
petethepig 7y ago
Another example is Russian 2011 elections: https://akarlin.com/2011/12/measuring-churovs-beard/ https://akarlin.com/2011/12/measuring-churovs-beard/
- totetsu 7y ago
  Here is a study applying the same integer percentages analysis to the 2018 elections in Russia https://rss.onlinelibrary.wiley.com/doi/full/10.1111/j.1740-9713.2018.01141.x https://rss.onlinelibrary.wiley.com/doi/full/10.1111/j.1740-...
kauffj 7y ago
At least to me, the discontinuities in things like TANF, Medicaid, CHIP, etc. are some of the greatest signs of political dysfunction. There's nothing remotely partisan about these being a bad thing. _Everyone_ should agree that these make no sense and mis-incentivize behavior. Yet these flaws remain for decades despite being known and discussed for approximately the entirety of their existence.
- thedance 7y ago
  It’s the stated goal of the party in power to throw as many kids off food assistance as possible. If the program has quirks that is by design.
  - kortilla 7y ago
    What is “the party in power”? Democrats control the House and Republicans control the Senate. No laws can be passed right now without bipartisan support.
    - thrower123 7y ago
      Moreover, these discontinuities and the perverse incentives that they lead to on the cusps have been elements of these programs for longer than I've been alive.
      - thedance 7y ago
        Depending on how long you’ve been here, you may have been living under a Reagan-esque conservative regime the whole time. Over my entire life I’ve seen only actual republican policies, or policies of weak-minded Democrats easily baited into acting like Republicans. There hasn’t been a sincere and effective advocate for the poor in America since LBJ.
        smcl 7y ago
        You're being downvoted but you're correct. A glance at some of the potential Democratic presidential nominees tells the whole story: Biden (classic case of "weak-minded Democrats easily baited into acting like Republicans"), Warren (actually was a Republican, during the Reagan years no less!), Buttigieg (previously a firm supporter of M4A then was somehow persuaded to water it down to "Medicare for all...who want it") ... Bloomberg!
raviolo 7y ago
Would creating, say, online marketplace to help people lose desired amount of money with certainty - for example, via some sort of specially crafted financial instrument - violate any applicable rules & regs? Idea for the next YC batch?
- PhantomGremlin 7y ago
  You don't need to do anything special for this. I don't see the need for a startup to "help" with this. Existing options are already sufficient. It would take a financial professional less than a day to write up a comprehensive guide to such a strategy. E.g. if you want to lose $5,000 just buy a bunch of options that are way out of the money, that have a perhaps 1% chance of paying off. 99% of the time you lose $5,000, which is what you wanted. 1% of the time you win $500,000, which is a nice problem to have. That payoff will probably dwarf the financial penalty of whatever discontinuity you were trying to work around.
- ahakki 7y ago
  Charitable contributions can be deducted from taxable income in a lot of places.
gowld 7y ago
Sickening of these "unintended" consequences are that programs designed to help the poor end up being used by the rich and well-connected -- parents who "disown" their children" to make them look poor during college application, or who lie about or overemphasize their racial background to claim affirmative action rewards.
- PhantomGremlin 7y ago
  parents who "disown" their children" to make them look poor during college application I'm sure this happens. Parents can also get divorced, the kid then becomes a dependent of a poor parent. But it goes both ways. E.g. in a case I'm familiar with, a friend of my daughter: 1) her father died when she was young, IIRC a junior in high school 2) now she's poor, mother doesn't have or make much money. Fortunately there are things like life insurance and social security survivors benefits to help. 3) colleges like to give good financial aid packages to poor people. 4) mother remarries, but this is a 2nd marriage and so people are older, with existing children 5) now mother is part of a household with a lot higher income; sucks for the daughter because now she isn't getting jack-shit in terms of college financial aid I certainly wouldn't expect her new stepfather to want to pay $20,000 or more per year tuition for an 18 year old girl whose mother he just married. Especially when he has his own kids to think of for college. Unfortunately for the kid, community college became the only option.
gowld 7y ago
The youth-sports thing has spread to academics, where parents "redshirt" their kids in order to get them higher GPAs and test scores which are curved against their grade-level peers not their age. College admissions committees are easily duped by this.
btilly 7y ago
The perverse incentives around these discontinuities is one of the worst misfeatures of programs intended to help people. Here is a real example. My niece wound up with 3 kids, divorced, with inconsistent child support payments. So she went on food stamps. She was looking for a better job. She found one, interviewed, and they wanted to hire her. But the salary that they offered was $0.50/hour too much for her to stay on food stamps, and was less than her current job. Thanks to union regulations, the person who wanted to hire her couldn't pay her less than the standard salary. The result is that she did not take the job. A common result when Congress takes note of perverse incentives like this is that they introduce a more complex program with specific terms that address specific problems that emerged. The problem is that by creating more brackets and more complex rules you usually create MORE cliffs with perverse incentives (though the perverse incentive at each cliff tends to be less). Another solution is to introduce rules that attempt to identify people who are "abusing the system" and punish them. So, for example, you can only be on welfare for a limited time because people got outraged that single mothers wound up on welfare for a long time. However those single mothers were acting that was in part because they were better off on welfare looking after their own kids than they were in a low end job and paying for daycare. Stereotypically the first type of solution is characteristic of Democrats and the second of Republicans. But the truth is that both parties do a lot of both solutions.
- dragonwriter 7y ago
  > The perverse incentives around these discontinuities is one of the worst misfeatures of programs intended to help people. This is a key motivation for replacing many of those programs with UBI funded by progressive taxes.
  - tjr225 7y ago
    Either that or a more progressive stance on socialist policies that provide basics to everyone. At least with socialist style policies there isn't the possibility of those spending their UBI on junk food or wine our whatever, but I really would prefer either to the current state of affairs.
brilee 7y ago
The Polish test distribution is an interesting counterexample: it demonstrates that there is _not_ a discontinuity. Instead of failing immediately at a score of 29, the graph suggests that you start failing probabilistically, with greater probability as your score drops. The bump at 30 is merely the mechanism by which this happens. Thus, this is in fact an example of a continuous threshold of the type Dan is recommending.
mgraczyk 7y ago
I have firsthand experience of the frustration that these sort of discontinuities can cause. I lost all financial aid and nearly all "scholarship" money my senior year of undergrad after my 6 month coop at Intel put me over some income limits (probably around $33k per year). All told, I was probably ~$5k ahead compared to where I would have been with the scholarships and without the income. Still, it would have been nice to do something more productive than spend six months at Intel for ~5k after taxes.
- vxNsr 7y ago
  Presumably the experience itself helped you get other jobs that would’ve been unattainable had you not had a prestigious internship at intel.
  - daniel-thompson 7y ago
    Sure, but the person would have been in the same boat no matter what specific logo was hanging over the door.
  - mgraczyk 7y ago
    Intel is not prestigious in the US software job market. Literally nobody I have interviewed with has ever asked me about my time at Intel.
knzhou 7y ago
There's a possibility that a discontinuity in data analysis might have an impact on fundamental physics. Many dark matter detection experiments rely on detecting an annual modulation, i.e. an excess of detection events later in the year, when the Earth would be going into the 'dark matter wind'. This helps one distinguish the desired signal from backgrounds that don't change throughout the year, like cosmic rays or ambient radioactivity. One particular experiment has been claiming a positive detection for two decades, leading to a lot of confusion in the field. It was recently argued [0] that this is due to a discontinuity in their data analysis. The team might be analyzing their annual modulation by subtracting out the average rate in each year, leading to a discontinuity at each year boundary. So if their detection rate is slowly going up, e.g. due to detector aging, it would look like an annual modulation, where the rate is lower in the beginning of the year and higher at the end! 0: https://arxiv.org/abs/2002.00459 https://arxiv.org/abs/2002.00459
jennyyang 7y ago
Losing money on put options won't adjust your income very much. You can only claim up to $3000/year on capital losses against income. So the example wouldn't work unless some of the income was also capital gains.
fyp 7y ago
Another real world example I saw recently was in programming competitions. There's a tradition of displaying a color for your username based on your ELO rating (for example people would brag about being Red or Yellow on topcoder). So people tend to stop competing forever after hitting the next level just to preserve their color! Graph distribution of ratings: https://codeforces.com/blog/entry/52470 https://codeforces.com/blog/entry/52470
fizixer 7y ago
Off-topic: I'm looking at turnout histograms and I'm having the hardest time making sense of it. Why is registered voter count on the y-axis instead of x-axis, since that should be the independent variable? Then I realized/recalled that is what histograms do. They flip the plot between the two axis. The original, non-histogram, plot is really turnout (y-axis) vs registered-voters. But that would look very different (generally such plots are very noisy, with a running-average that mimics a horizontal line). Then, if you wish to know what's the distribution of registered-voters with respect to turnout, you take a histogram. edit: on second thought, the plot still doesn't make sense. The y-axis should be # of polling stations, not # of registered-voters. edit 2: This article [0] has a plot that confirms my suspicion (y-axis is supposed to be number/frequency of polling stations, not number of registered voters). [0] https://doi.org/10.1111/j.1740-9713.2018.01141.x https://doi.org/10.1111/j.1740-9713.2018.01141.x
BurningFrog 7y ago
The Swedish system solves much of this, at a price. In Sweden, the principle is that everyone pay into the system, and everyone gets benefits from it. So everyone, rich or poor, gets a $130/month payment per child under 18. There are many other examples. The price is that while the US has a very progressive tax system, where high income earners pay a lot of tax, while the low & middle pay very little, in Sweden everyone pays a lot of tax. It (kinda) works because everyone also get a lot back from the system. So Sweden has very high taxes, but most people get similar value back. You can think of it as a forced savings system in some ways.
nazgulnarsil 7y ago
Another example is that many men who are 5'10" and 5'11" report being six foot, which shows up in a lump on an otherwise normal distribution.
bemmu 7y ago
Our post office has a shipping discount, where you get 10% off all of your shipments you've sent during the month if you send 1000 packages or more. Once you get near this limit, you get into the perverse situation where it makes sense to send empty packages to nowhere.

644 points by janvdberg 7y ago

The youth sports discontinuity was a problem for me when I became old enough to play little league, but was exploited by me when I should have moved on to Teener League. I was born on the cut-off date for Little League, so I was the youngest player on the team my first year (and the youngest for my grade the other years.) Do to ambiguity in how the cut-off date wording was written, I ended up (legally) playing a fourth year when I was 13. I was never a big kid but at this point I was certainly bigger than all the 10 year-olds and more importantly had gained coordination and experience. It was my favorite year playing baseball. (As an aside, I paid karma for it the next year ... I spent eighth grade in a city Teener League where I was once again the smallest, least experienced kid. And the city league was way more cut-throat than what I'd experienced in the suburban setting my previous four years.)

eloff 7y ago
I was always small until about age 16, and I always sucked at sports and never really got into them - partly as a result. I wonder if we shouldn't group kids by size for sporting activities instead of by age. There's a famous statistic in Canada that NHL players are much more likely to be born in January and February than September-December. The reason being is they were nearly a year older than other kids they were paired with, so they did better at the sport and thus kept it up as they grew. Seems silly.
- EpicEng 7y ago
  >I wonder if we shouldn't group kids by size for sporting activities instead of by age. Depending on how small your buckets are, you may end up with a scarcity problem (players and admins/coaches). Also, age matters a lot in regards to coordination. A 13 year old who is roughly the size as a ten year old will, on average, have a large advantage. Some people just aren't cut out for athletics genetically. Some grow later on and may or may not be interested. Age seems like a fair sorting criteria and general enough to not introduce too much complexity.
  - joombaga 7y ago
    > A 13 year old who is roughly the size as a ten year old will, on average, have a large advantage. This is an interesting claim. How much is a large advantage? Do you mean in hockey specifically? Or in athletics? Or any given task?
  - bradlys 7y ago
    > Some people just aren't cut out for athletics genetically. Some grow later on and may or may not be interested. Age seems like a fair sorting criteria and general enough to not introduce too much complexity. Age isn't particularly fair but it isn't the worst either. As a kid, being around kids younger than you can be really displeasing. When you're a kid, the only thing you want is to be treated like you're older/better than you are. If you keep getting put on teams for people who are small - it's likely you're being put on teams for people who are smaller than you. I had to play baseball with 7-yr olds for about 3 years. It wore me down as a kid. I gave up on baseball at that point and said I wasn't doing it anymore. The reason I had to play with them is because no coach wanted me on their team because they saw me as too small. (Small town, they didn't group by age as much as they did by size) I'd see kids go up to bigger-kid teams and get bigger but I stayed the same size. As a kid - it was super disheartening to be stuck with the same 7 to 8 year olds for all that time and seeing people you used to play with in the bigger kid league. It sucked. That said - baseball is probably the ONLY sport I can imagine being where you could move kids up by age and not by size as much. Football, soccer, basketball, etc. all involve a serious size component to them whereas baseball is less so - in my mind. For reference - I grew up to be a normal sized adult. I was just super late on the curve compared to my peers.
    - SamReidHughes 7y ago
      When I was a kid, our club soccer travel team of 4th graders beat an intramural team of 6th graders by 3 goals. Our coach lost $100, because he'd bet we'd win by at least 4. I think soccer and basketball much moreso involve a coordination and fitness component than size. In youth soccer, you have to outrun the other kids and handle the ball well. Messi is 5'7". In basketball, of course, height does help a lot there, but amongst local kids, better to be able to make shots, dribble, and get around the court. Football was the only sport that segregated by size in my school system's leagues, in middle school. Well, besides wrestling, of course. They're contact sports.
- alexis_fr 7y ago
  > The reason being is they were nearly a year older than other kids they were paired with. I’m amused that the kids who did worse are absolutely necessary for the kids who do better. They end up getting wasted by the process, demotivated, but they are a necessary brick to step upon. It’s the same consideration when talking about male suicide. Are they necessary for others to feel good? We could solve a good part of it as a society, but at the expense of providing an environment where males fail less, have a better social net, receive more love, and are less pushed to succeed in their career to be recognized. So we could solve it, but it may cost our economic growth. Is that why male suicide isn’t getting solved? It’s getting less funding than even dog shelters, and less attention than much smaller problems.
  - nl 7y ago
    It’s the same consideration when talking about male suicide. Are they necessary for others to feel good? No. There's no evidence at all to support this view. In fact there is evidence to support the view that people who feel good when others feel bad are more likely to have suicidal tendencies.
    - alexis_fr 7y ago
      Then... why don’t we act against it? Isn’t it, then, more urgent than other topics? It doesn’t seem like we care, given we always treat male complaints as crybabies.
- jmmcd 7y ago
  > I wonder if we shouldn't group kids by size for sporting activities instead of by age. This is how it's done in rugby in New Zealand and maybe a few other countries, but not most. It's much more important in rugby than in baseball!
habosa 7y ago
I had the exact same experience. I was one of the youngest people in my year and one of the worst players on my team. Until my age 13 season, when they wouldn't let me move up into the teenager league because of a one=month difference in age. So I was pitching to kids who had just turned 10 ... I threw a lot of strikeouts that year and hit my only home run ever haha.

leto_ii 7y ago

The Economist recently had some more detailed plots on the crack cocaine discontinuities: https://www.economist.com/graphic-detail/2020/01/18/smoking-gun-evidence-emerges-for-racial-bias-in-american-courts https://www.economist.com/graphic-detail/2020/01/18/smoking-...

cs702 7y ago

Any rules that can be gamed, sooner or later, inevitably, will be gamed. The "suspicious discontinuities" shown in this fantastic post are evidence for it. It seems to be an Iron Law of Human Nature.

hn_throwaway_99 7y ago
This 'Iron Law of Human Nature' is a corollary of Goodhart's Law: https://en.wikipedia.org/wiki/Goodhart%27s_law https://en.wikipedia.org/wiki/Goodhart%27s_law
ChainOfFools 7y ago
what gets measured gets treasured

throwaway023421 7y ago

The statistics on the amount of cocaine show an appalling pattern of lying and false evidence from the police. It's even more appalling that people hardly acknowledge such bias.

lolc 7y ago
Please do not jump to conclusions and read the footnote which addresses that point explicitly: "drug seizure records, amounts seized do not appear to be the cause of this change."
- mjw1007 7y ago
  That seems to mean "if you assume that the drug seizure records are not falsified, you can conclude that the police are not lying or producing false evidence".
  - ls612 7y ago
    It means the police are not falsifying records of drug seizures to make them hit any of the statutory thresholds. They may be falsifying them in other ways but this can’t be verified one way or another by this data.
- tqi 7y ago
  I do not have access to the original paper, but author's assessment that the bunching is due to prosecutorial discretion is a little puzzling to me. If it is true that prosecutors are choosing to prosecute cases that are above the cutoff at a higher rate than those below, I would have expected everything above 280g to increase, rather than a solitary spike at 280g?
  - wahern 7y ago
    From Note 1: > prosecutors can charge people for amounts that are not the same as the amount seized and then notes If someone is caught with 500g you can simply charge 280g and make your life easier. If you charge 500g the defendant will argue it was just 450g, which even if irrelevant makes the case seem weaker to the jury--death by a thousand cuts. But if you charge 280g and present evidence of 500g, it makes the case seem more like a slam-dunk to the jury.

ceejayoz 7y ago

> One reason people were looking for ways to lose money was that, in the U.S., there's a hard income cutoff for a health insurance subsidy at $48,560 for individuals (higher for larger households; $100,400 for a family of four). There are a number of factors that can cause the details to vary (age, location, household size, type of plan), but across all circumstances, it wouldn't have been uncommon for an individual going from one side of the cut-off to the other to have their health insurance cost increase by roughly $7200/yr. That means if an individual buying ACA insurance was going to earn $55k, they'd be better off reducing their income by $6440 and getting under the $48,560 subsidy ceiling than they are earning $55k. This is an incredibly dumb way to structure things.

hammock 7y ago
https://en.wikipedia.org/wiki/Welfare_trap https://en.wikipedia.org/wiki/Welfare_trap
thundergolfer 7y ago
Too many smart people in the US are working to invent things like the 'Double Irish with a Dutch Sandwich'[1] rather than fixings these massive equity and fairness problems at the bottom end. 1. https://www.investopedia.com/terms/d/double-irish-with-a-dutch-sandwich.asp https://www.investopedia.com/terms/d/double-irish-with-a-dut...
- deleted 7y ago
  [deleted]
quickthrowman 7y ago
There are 0 Congresspeople that are near the threshold, which could be related.. Congress seems to focus on ensuring wealthy citizens and corporations gain more wealth, and not making things fair for everyone else.
myself248 7y ago
What's eye-opening is the author's point about _how_ many people go about ditching some income at the last minute -- by buying a particular type of financial product whose value is likely to go to zero. Which has the effect of transferring their wealth to someone else (the vendor of the financial product) who just sold something that was effectively worth nothing, for a great deal of money. It's the most bizarre sort of wealth redistribution I've ever heard of.

ww520 7y ago

IRS would do well catching tax evasion by running some statistic models to find suspicious discontinuities.

jacques_chester 7y ago
They do. Tax agencies worldwide have used statistical techniques for decades.
- TeMPOraL 7y ago
  Benford's law is probably the most known example. https://en.wikipedia.org/wiki/Benford%27s_law https://en.wikipedia.org/wiki/Benford%27s_law

lkbm 7y ago

OKCupid has a graph of reported height for men[0]. It's both shifted 2 inches to the right of average, but also slightly flattened at the normal peak of 5'10". It's not nearly as pronounced as the graphs in this post, but it's still notable. [0] https://theblog.okcupid.com/the-big-lies-people-tell-in-online-dating-a9e3990d6ae2 https://theblog.okcupid.com/the-big-lies-people-tell-in-onli...

hammock 7y ago
Both men and women showed height above the national average. As a result I am more inclined to believe that there is selection bias in OKCupid audience (more white people, less minorities) than that there is such widespread deception going on.
- birdyrooster 7y ago
  Exactly. Not to mention short people may have opted out of dating because they lack a perceived fitness for dating.
  - gowld 7y ago
    Or tall people opt out of OKCupid because they can date offline.
    - birdyrooster 7y ago
      Or since it's so easy for tall people to date offline, they choose OKCupid because it's even easier due to the asynchronous model and network effect. They get more out of the algorithms than shorter people since more people are attracted to them.
  - deleted 7y ago
    [deleted]
- opportune 7y ago
  Or it’s self reported and on average people fibbed up their height a smidge

maxmcd 7y ago

People playing speed chess (presumably) get fixated on improving their Elo rating by the next 100 point span, leading to spikes every 100 rating points in the distribution: https://lichess.org/stat/rating/distribution/bullet https://lichess.org/stat/rating/distribution/bullet

selimthegrim 7y ago

How about the US killing like 10 “Al Qaeda No 2”s in a row for a while in Iraq

mumblemumble 7y ago
If you order your hit list right, you can kill a continuous streak of #2s, until there's only one person left.
- kevin_thibedeau 7y ago
  With only a few 100k casualties in collateral damage.
  - banads 7y ago
    And twice as many more potential #2s spring up as a result
refurb 7y ago
How is that weird? #2 gets killed, new #2 takes his/her place, #2 gets killed.
- selimthegrim 7y ago
  Do you really think they were all actually No 2s? That AQI had that bad opsec? Don't we hit the No 3 too every once in a while?
  - refurb 7y ago
    Presumably the #3 became the #2, when the original #2 was killed. I see your point - do they just say #2 to sound impressive, however, they seem to know the structure of AQI pretty well and folks get promoted into that role when a death occurs, so I’m going with “likely true”.

aeturnum 7y ago

This is a lovely post and good general demonstration on this phenomenon. The drug charging graph is particularly stark. I think the most interesting graph is the final one, for marathon finishing times. The idea that people will fudge numbers to meet (or avoid) official definitions is commonly believed (and shown repeatedly here). It's more interesting to observe that it's not just people using motivated reasoning, but also that people will alter their performance to hit highly visible targets.

Wehrdo 7y ago
I think another factor for the marathon finishing time discontinuities is the use of pacers --- people who run carrying signs at a pre-defined speed (usually targeting a specific finishing time, e.g. 3:15). Lots of people who have finishing goals will run in a pack with this person so they know they're going fast enough, then will all finish just under the target time.

stared 7y ago

Ad Polish end of high school exams: quite a few years ago I created an interactive widget to explore it https://github.com/stared/delab-matury https://github.com/stared/delab-matury. There are a few jokes about the Matural Distribution (Matura is the name of this exam) or the Polish Gaussian. It is the Polish language, which is the most discontinuous. However: - There are quite a few scores for the essay which are subjective (e.g. on the style). - It is an official procedure that in the case of results on the edge, the person marking should mark an ambiguous score in the favour of the student.

ehnto 7y ago
> It is an official procedure that in the case of results on the edge, the person marking should mark an ambiguous score in the favour of the student Given that it's subjective, I find that a really generous and positive take on marking protocol. It takes some perspective to note that while you can't see the value in someone's work, there may still be value in it. edit: After reading through the article in full, I understand perhaps that's not what's going on exactly. Just teachers trying their hardest to find ways not to fail the exam as it is such an important life step for that person. Still a virtuous thing to do!
- stared 7y ago
  I don't consider it virtuous! By pushing more to pass: - either the next year the problems will be more difficult, - or it devaluates the worth of passing an exam. Also, 30% is very low (especially as such cut-off are for the basic level exams, not advanced level exams). You get the high school diploma, but it is not something that is enough to get to any univ. that makes any sense (some will take such students, but only as they are being funded on the level of enrolment OR they are private and are essientially "a bribe-in rates for a diploma" style).
  - ehnto 7y ago
    Is it not a final exam for the entire schooling process? If it is, I don't think there's anything wrong with letting people who attended, tried and got close, a passing grade. As much as we value merit, the real world actually isn't a meritocracy, and high school isn't much of a measure for how successful someone has the potential to be. I think you begin to be right as people move into academia though, certainly you want people who are actually good at the subject to be the ones passing university and going into the work force.

deleted 7y ago

[deleted]

petethepig 7y ago

Another example is Russian 2011 elections: https://akarlin.com/2011/12/measuring-churovs-beard/ https://akarlin.com/2011/12/measuring-churovs-beard/

totetsu 7y ago
Here is a study applying the same integer percentages analysis to the 2018 elections in Russia https://rss.onlinelibrary.wiley.com/doi/full/10.1111/j.1740-9713.2018.01141.x https://rss.onlinelibrary.wiley.com/doi/full/10.1111/j.1740-...

kauffj 7y ago

At least to me, the discontinuities in things like TANF, Medicaid, CHIP, etc. are some of the greatest signs of political dysfunction. There's nothing remotely partisan about these being a bad thing. _Everyone_ should agree that these make no sense and mis-incentivize behavior. Yet these flaws remain for decades despite being known and discussed for approximately the entirety of their existence.

thedance 7y ago
It’s the stated goal of the party in power to throw as many kids off food assistance as possible. If the program has quirks that is by design.
- kortilla 7y ago
  What is “the party in power”? Democrats control the House and Republicans control the Senate. No laws can be passed right now without bipartisan support.
  - thrower123 7y ago
    Moreover, these discontinuities and the perverse incentives that they lead to on the cusps have been elements of these programs for longer than I've been alive.
    - thedance 7y ago
      Depending on how long you’ve been here, you may have been living under a Reagan-esque conservative regime the whole time. Over my entire life I’ve seen only actual republican policies, or policies of weak-minded Democrats easily baited into acting like Republicans. There hasn’t been a sincere and effective advocate for the poor in America since LBJ.
      - smcl 7y ago
        You're being downvoted but you're correct. A glance at some of the potential Democratic presidential nominees tells the whole story: Biden (classic case of "weak-minded Democrats easily baited into acting like Republicans"), Warren (actually was a Republican, during the Reagan years no less!), Buttigieg (previously a firm supporter of M4A then was somehow persuaded to water it down to "Medicare for all...who want it") ... Bloomberg!

raviolo 7y ago

Would creating, say, online marketplace to help people lose desired amount of money with certainty - for example, via some sort of specially crafted financial instrument - violate any applicable rules & regs? Idea for the next YC batch?

PhantomGremlin 7y ago
You don't need to do anything special for this. I don't see the need for a startup to "help" with this. Existing options are already sufficient. It would take a financial professional less than a day to write up a comprehensive guide to such a strategy. E.g. if you want to lose $5,000 just buy a bunch of options that are way out of the money, that have a perhaps 1% chance of paying off. 99% of the time you lose $5,000, which is what you wanted. 1% of the time you win $500,000, which is a nice problem to have. That payoff will probably dwarf the financial penalty of whatever discontinuity you were trying to work around.
ahakki 7y ago
Charitable contributions can be deducted from taxable income in a lot of places.

gowld 7y ago

Sickening of these "unintended" consequences are that programs designed to help the poor end up being used by the rich and well-connected -- parents who "disown" their children" to make them look poor during college application, or who lie about or overemphasize their racial background to claim affirmative action rewards.

PhantomGremlin 7y ago
parents who "disown" their children" to make them look poor during college application I'm sure this happens. Parents can also get divorced, the kid then becomes a dependent of a poor parent. But it goes both ways. E.g. in a case I'm familiar with, a friend of my daughter: 1) her father died when she was young, IIRC a junior in high school 2) now she's poor, mother doesn't have or make much money. Fortunately there are things like life insurance and social security survivors benefits to help. 3) colleges like to give good financial aid packages to poor people. 4) mother remarries, but this is a 2nd marriage and so people are older, with existing children 5) now mother is part of a household with a lot higher income; sucks for the daughter because now she isn't getting jack-shit in terms of college financial aid I certainly wouldn't expect her new stepfather to want to pay $20,000 or more per year tuition for an 18 year old girl whose mother he just married. Especially when he has his own kids to think of for college. Unfortunately for the kid, community college became the only option.

gowld 7y ago

The youth-sports thing has spread to academics, where parents "redshirt" their kids in order to get them higher GPAs and test scores which are curved against their grade-level peers not their age. College admissions committees are easily duped by this.

btilly 7y ago

The perverse incentives around these discontinuities is one of the worst misfeatures of programs intended to help people. Here is a real example. My niece wound up with 3 kids, divorced, with inconsistent child support payments. So she went on food stamps. She was looking for a better job. She found one, interviewed, and they wanted to hire her. But the salary that they offered was $0.50/hour too much for her to stay on food stamps, and was less than her current job. Thanks to union regulations, the person who wanted to hire her couldn't pay her less than the standard salary. The result is that she did not take the job. A common result when Congress takes note of perverse incentives like this is that they introduce a more complex program with specific terms that address specific problems that emerged. The problem is that by creating more brackets and more complex rules you usually create MORE cliffs with perverse incentives (though the perverse incentive at each cliff tends to be less). Another solution is to introduce rules that attempt to identify people who are "abusing the system" and punish them. So, for example, you can only be on welfare for a limited time because people got outraged that single mothers wound up on welfare for a long time. However those single mothers were acting that was in part because they were better off on welfare looking after their own kids than they were in a low end job and paying for daycare. Stereotypically the first type of solution is characteristic of Democrats and the second of Republicans. But the truth is that both parties do a lot of both solutions.

dragonwriter 7y ago
> The perverse incentives around these discontinuities is one of the worst misfeatures of programs intended to help people. This is a key motivation for replacing many of those programs with UBI funded by progressive taxes.
- tjr225 7y ago
  Either that or a more progressive stance on socialist policies that provide basics to everyone. At least with socialist style policies there isn't the possibility of those spending their UBI on junk food or wine our whatever, but I really would prefer either to the current state of affairs.

brilee 7y ago

The Polish test distribution is an interesting counterexample: it demonstrates that there is _not_ a discontinuity. Instead of failing immediately at a score of 29, the graph suggests that you start failing probabilistically, with greater probability as your score drops. The bump at 30 is merely the mechanism by which this happens. Thus, this is in fact an example of a continuous threshold of the type Dan is recommending.

mgraczyk 7y ago

I have firsthand experience of the frustration that these sort of discontinuities can cause. I lost all financial aid and nearly all "scholarship" money my senior year of undergrad after my 6 month coop at Intel put me over some income limits (probably around $33k per year). All told, I was probably ~$5k ahead compared to where I would have been with the scholarships and without the income. Still, it would have been nice to do something more productive than spend six months at Intel for ~5k after taxes.

vxNsr 7y ago
Presumably the experience itself helped you get other jobs that would’ve been unattainable had you not had a prestigious internship at intel.
- daniel-thompson 7y ago
  Sure, but the person would have been in the same boat no matter what specific logo was hanging over the door.
- mgraczyk 7y ago
  Intel is not prestigious in the US software job market. Literally nobody I have interviewed with has ever asked me about my time at Intel.

knzhou 7y ago

There's a possibility that a discontinuity in data analysis might have an impact on fundamental physics. Many dark matter detection experiments rely on detecting an annual modulation, i.e. an excess of detection events later in the year, when the Earth would be going into the 'dark matter wind'. This helps one distinguish the desired signal from backgrounds that don't change throughout the year, like cosmic rays or ambient radioactivity. One particular experiment has been claiming a positive detection for two decades, leading to a lot of confusion in the field. It was recently argued [0] that this is due to a discontinuity in their data analysis. The team might be analyzing their annual modulation by subtracting out the average rate in each year, leading to a discontinuity at each year boundary. So if their detection rate is slowly going up, e.g. due to detector aging, it would look like an annual modulation, where the rate is lower in the beginning of the year and higher at the end! 0: https://arxiv.org/abs/2002.00459 https://arxiv.org/abs/2002.00459

jennyyang 7y ago

Losing money on put options won't adjust your income very much. You can only claim up to $3000/year on capital losses against income. So the example wouldn't work unless some of the income was also capital gains.

fyp 7y ago

Another real world example I saw recently was in programming competitions. There's a tradition of displaying a color for your username based on your ELO rating (for example people would brag about being Red or Yellow on topcoder). So people tend to stop competing forever after hitting the next level just to preserve their color! Graph distribution of ratings: https://codeforces.com/blog/entry/52470 https://codeforces.com/blog/entry/52470

fizixer 7y ago

Off-topic: I'm looking at turnout histograms and I'm having the hardest time making sense of it. Why is registered voter count on the y-axis instead of x-axis, since that should be the independent variable? Then I realized/recalled that is what histograms do. They flip the plot between the two axis. The original, non-histogram, plot is really turnout (y-axis) vs registered-voters. But that would look very different (generally such plots are very noisy, with a running-average that mimics a horizontal line). Then, if you wish to know what's the distribution of registered-voters with respect to turnout, you take a histogram. edit: on second thought, the plot still doesn't make sense. The y-axis should be # of polling stations, not # of registered-voters. edit 2: This article [0] has a plot that confirms my suspicion (y-axis is supposed to be number/frequency of polling stations, not number of registered voters). [0] https://doi.org/10.1111/j.1740-9713.2018.01141.x https://doi.org/10.1111/j.1740-9713.2018.01141.x

BurningFrog 7y ago

The Swedish system solves much of this, at a price. In Sweden, the principle is that everyone pay into the system, and everyone gets benefits from it. So everyone, rich or poor, gets a $130/month payment per child under 18. There are many other examples. The price is that while the US has a very progressive tax system, where high income earners pay a lot of tax, while the low & middle pay very little, in Sweden everyone pays a lot of tax. It (kinda) works because everyone also get a lot back from the system. So Sweden has very high taxes, but most people get similar value back. You can think of it as a forced savings system in some ways.

nazgulnarsil 7y ago

Another example is that many men who are 5'10" and 5'11" report being six foot, which shows up in a lump on an otherwise normal distribution.

bemmu 7y ago

Our post office has a shipping discount, where you get 10% off all of your shipments you've sent during the month if you send 1000 packages or more. Once you get near this limit, you get into the perverse situation where it makes sense to send empty packages to nowhere.