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Do We Need a 37-Cent Coin? (2009)
- gus_massa 2y agoIportant first comment in the blog: > Just to summarize how commenter, Jeffrey Shallit, addresses the (1, 3, 11, 37) solution: this is the best way to use the Greedy algorithm to select coins. However, (1, 5, 18, 25) and (1, 5, 18, 29) are tied for the actual solutions. [...]
- TZubiri 2y agoI thought it was going to be about how there was 3700% inflation since coins were actually a useful concept. It's probably just better to go for eliminating the cent and the nickel and making a 2.5$ coin.
- SoftTalker 2y agoI’d go farther and eliminate all but the quarter.
- chipsrafferty 2y agoAnd make it illegal to sell any service or product that isn't ending in 0.25, 0.5, 0.75, and 1.00. Tax must be included and listed in advance for all sales prices. A few tiny pieces of candy? Sell more at once. Want to charge a dollar for something but tax makes it 1.07? Either eat the tax yourself and offer it for 1.00 post tax, or raise the price and charge 1.25 for it.
- im3w1l 2y agoIt's quite surprising to me how the US still has the penny. Like its value is less than the cost of carrying it around.
- zahlman 2y agoCanada gave up on it over a decade ago (https://en.wikipedia.org/wiki/Penny_(Canadian_coin) https://en.wikipedia.org/wiki/Penny_(Canadian_coin)).
- cduzz 2y agoI've said before, I'll say again: We should have the $0.1 and $0.5 coins and everything should be rounded to that. There's no reason to have $0.01 or even $0.05 precision. The value of the dollar, these days, has inflated to the point where there's simply no practical difference between $0.01 and $0.03 or $0.08 in everyday life, when dealing with cash transactions. You could certainly track $0.01 in digital account tracking, but the coin is silly. And -- with payment processing fees, places dealing with cash or card processing would still see less cost in "rounding down" than paying for card processing.
- chgs 2y agoPrices in America are wired. Bought a beer yesterday waiting for the train. Claimed it was $7, actual price $7.62 (which Amex coincidently converted to exactly £6.00) If I’d paid in cash I’d have to pay with at least a 2 cent coin (and likely need a 1 or 3 in change), despite the nice round number Until America changes to advertise things at the actual price rather than a partial price, I don’t see how getting rid of 1 cent coins works.
- cduzz 2y agoIt'd cost $7.6 if you pay in cash and $7.62173451123 if you pay via a card? (and, if I were to pass the "small change" bill, I'd, by fiat, make it so that it'd still be "$7.6" even if it was $7.68 -- and the vendors would still come out ahead because the $0.08 lost from rounding down is much less than the $0.23 in card processing fees that comes with a 3% surcharge from your payment processors.)
- zahlman 2y agoDoes the UK include VAT in all listed prices? I don't recall it working that way in continental Europe, and it certainly doesn't work that way in Canada with our equivalent (nor in the US, as you discovered). That said, advertised prices are commonly not "round" in the first place. In Canada, we simply round the figure on the bill when paying cash.
- analog31 2y agoPeople are superstitious about math, and fearful that rounding to the nearest nickel, or dime, will result in them getting ripped off. Also, it's an admission that the government has given up on inflation. This is the country that gave up on the metric system because it involved too much math.
- HPsquared 2y agoI'd suspect they rejected the metric system because it would have cost money to change everything over. The argument would presumably have gone something like "we can't have the federal government imposing a cost on the citizens / corporations".
- crazygringo 2y agoExactly. It had nothing to do with "too much math" -- I think everyone appreciates metric uses less math, and we all learn it in school anyways for science classes. It's the cost of change. Replacing every speed limit sign, spending decades where half the cookbooks you own use oven temperatures in °F and half use °C. Years of confusion where someone says they were going 60 and you have to ask if they mean mph or kph. Not to mention changing the size of every milk container, and so forth...
- ryandrake 2y agoI'm not sure I buy that excuse. For packaged goods and so on, you don't have to change any sizes of things. Just pick a date and change to a different package design. So nothing in your factory that produces 1 gallon milk jugs has to change except the graphic design needs to start saying 3.8L Milk instead of 1gal Milk. At that point, you can transition to change the physical size of things whenever it is convenient. For cars, most of them in the US already show mph and kph, so the switch should be easy. Leave old signs alone, but whenever new signs get built, build them in both units for a few years (65mph / 105kph) allowing you to gradually transition to metric. Repeat for everything else. You can gradually make the switch. Heck, some products (like soda and bullets) are already in liters and millimeters. I agree with the OOP. We refuse to even take the first steps to switch because of good ol stereotypical American paranoia: "If we switch to metric, all the companies will use it to make everything smaller and rip us off!" as if shrinkflation wasn't already a thing.
- excalibur 2y agoPeople need to be able to quickly do the math in their heads to make change. More efficient use of coins but harder for everyone involved is not a functional improvement.
- im3w1l 2y agoSome of the proposed schemes seem acceptable from that point of view, in particular 1, 3, 10, 25.
- qwerty456127 2y agoWe should better introduce $50, $100, $500, $1000 and $5000 coins. I'd love my entire salary to come in coins and to be able to pay for any purchase in coins conveniently.
- edward28 2y agoAnd easier to bankrupt yourself because of a hole in your wallet.
- Symbiote 2y agoIt wasn't that long ago when it would be normal to be paid in cash (notes and coins) at the end of the week or the end of the month. Depending on the job sector, this could be the 1970s or 1980s in Britain, for example.
- jareklupinski 2y agoperhaps if we reduce these coins to some units of digital currency so we don't have to physically carry them around, like bits, but for coins
- MacsHeadroom 2y agoHow are you going to prevent fraudulent double spending of these digital coins? You'd have to invent some kind of Byzantine Fault Tolerant (BFT) consensus method.
- codetrotter 2y agoSure, but then you’d need a way for all participants to agree on which transactions are valid. Maybe like a chain of blocks that hold transaction data, and each block is cryptographically linked to the previous one. Sounds pretty difficult. I doubt that anyone would be able to create anything like that any time soon, if ever.
- 2y ago
- Jianghong94 2y ago> Probability of a transaction resulting in value v is uniform from [0,99]. in reality, most of the transactions that use coins end up conforming to common existing coin combinations e.g. laundromats in US mostly price as multiples of quarters ($0.25)
- throwuxiytayq 2y agoThe $X.99 price thing should be forbidden and I'm deeply disappointed in humanity/customerity that we don't shun them and refuse to deal with them
- kijin 2y agoIt's even uglier in jurisdictions where sales tax is not included in the $X.99 price tag. The total amount you need to pay becomes something like $X+1.07 and you end up with a lot of of unexpected change. Edit: In the example, I meant X+1 dollars and 7 cents. Apologies for the ambiguous formula, it felt awkward to use parentheses inside of an amount.
- jagged-chisel 2y ago$X * 1.07, or $X + 7% (of $X)
- _hl_ 2y agoThis certainly contributed to people preferring card over cash, making merchants loose ~3% per transaction. That ship has long sailed, but it does male you wonder: if everything was priced at increments of, say, quarters, would enough people still use cash to offset the lost sales from the allegedly less appealing pricing?
- mitthrowaway2 2y agoI don't know, but I find I use cash much more readily when the price includes tax, because I can confirm ahead of time that the cash in my wallet is enough without breaking a 20 for a pile of coins.
- GolfPopper 2y agoWhy not just re-index the dollar so that coins are useful amounts of currency?
- herf 2y agoI was curious what the theoretical distribution of digits might be, did not know that there is an extension of Benford's law for later digits which suggests the uniform assumption is quite nearly right: https://en.wikipedia.org/wiki/Benford%27s_law#Generalization_to_digits_beyond_the_first https://en.wikipedia.org/wiki/Benford%27s_law#Generalization... Of course in real life, 50 cents and 99 cents are way more common.
- alexshendi 2y agoI think we need a 1337 cent coin!
- jjbxjbuydbguj 2y ago[flagged]
- totallymike 2y agoHi there. How are ya?
- matthewaveryusa 2y agoThe coins proposed are all prime, which makes sense to me intuitively. You'll always need a 1 coin. I'm curious if it's generally true that optimal coins for any given range starting at 0 will be primes?
- kijin 2y agoI take issue with the assumption that you always need a 1 coin. If we're going to go to such great lengths to minimize the number of coins, even at the cost of making real-life transactions more complicated, we could totally forgo the 1 coin and just have 2 and 5. If an amount ends in 1, you pay 5 and get two 2s back. Now you can have a coin system that is entirely primes!
- TheMechanist 2y agoTwo obvious problems: the fractional part of the price is not uniform over [00..99] and the system has 5 coins, since in 2021 minting for the half-dollar coin was restarted.
- orthoxerox 2y agoWhy is a 11-cent coin ridiculous? With nine of them you could pay for these X.99 products and not get a penny in return.
- Finnucane 2y agoYes, we should totally revamp our coins to suit the needs of retail marketing.
- umvi 2y agoBecause X.99 products are pre tax, so you really have to pay X.99 + X.99 * 0.0Y
- bitdivision 2y agoThis made me wonder about the origins of the 0.99 price. I had always thought it was largely to avoid theft, by ensuring the worker had to open the till for change on every transaction. Which makes sense if there's no sales tax, but if there is sales tax then you might as well round everything to the dollar. Possibly sales tax wasn't a thing when this became a common practice. Makes the argument for the psychological effect of 0.99 vs 1.00 much stronger these days though I suppose.
- zertrin 2y agoIn the US, sure, but most of the world display prices inclusive of tax. (at least from my experience in EU and Asia)
- zitterbewegung 2y agoMost efficient would be to start rounding purchases to the nearest five cents (if is isn't electronic) and get rid of the penny which costs more to produce than the penny is worth.
- NeoTar 2y agoBut an average one cent coin is involved in more than a single transaction - if you amortise the cost of the coin over every transaction it is involved in, then it’s much less than one cent. If the cost of metals in a coin is more than its value, you do have a point.
- sigio 2y agoIn the Netherlands we've been rounding to 5ct intervals for 20+ years now, and 1ct coins were abolished long ago. With the introduction of the euro, the 1ct and 2ct coins returned, but all shops still round to 5ct for cash transactions. Every time I return from Germany I have a handful of 1 and 2ct coins though, since they haven't done this, and most prices are X.99.
- kristianp 2y agoIn Australia the 1 and 2 dollar notes were removed from circulation decades ago too. $1 in 1984 and $2 in 1988. With respect to the 1c and 2c coins, isn't the metal in them worth more than the currency value?
- zitterbewegung 2y agoCost in metals and manufacturing cost. (just to clarify)
- dang 2y agoRelated: Do We Need a 37-Cent Coin? - https://news.ycombinator.com/item?id=1694075 https://news.ycombinator.com/item?id=1694075 - Sept 2010 (137 comments) Freakonomics: Do We Need a 37-Cent Coin? - https://news.ycombinator.com/item?id=864838 https://news.ycombinator.com/item?id=864838 - Oct 2009 (50 comments)
- abetusk 2y agoThere's a question on SE cstheory site that addresses the more general problem [0]. I wonder if this problem is still open. [0] https://cstheory.stackexchange.com/questions/5861/asymptotics-for-coin-changing https://cstheory.stackexchange.com/questions/5861/asymptotic...
- jmclnx 2y agonot anymore :) Personally, in the US, pennies, nickles and dimes should be eliminated. I think we are at the point were paper money $1, $2 and $5 should be replaced by coins. But that would cause a huge uproar in this country.
- kccqzy 2y agoI personally prefer bills (paper or plastic) because they are lighter weight than coins. I would very much like to see 25¢ bills. Some countries use plastic rather than paper for bills of small denomination. They feel more pleasant and probably last longer. I also prefer these.
- conductr 2y agoAt some point, that we are possibly near to, doesn’t the value of a dollar become so small that the fractions of a dollar that coins represent aren’t even worth dealing with? If so, and transactions just rounds to nearest dollar the we are basically expecting that over our lifetime it will nearly balance out without the need to think about it too much.
- efitz 2y agoTouching coins is icky.
- sigio 2y agoWay less then banknotes... bacteria etc don't like metals
- ChuckMcM 2y agoI love thinking about problems like that. Yes it is impractical and unlikely to result in any change but it also helps illuminate relationships (like # of coins in your change) that you might not otherwise see. Of course, as an economist Patrick (the person asking the question in the article not the author) ignores what is most important about choosing coins "Can the teller give you change quickly and accurately?" That is the important question because GDP depends on transaction flow, and anything that hinders transaction flow is a net negative on GDP[1]. Using the Suica card in Japan I was reminded again of how useful it would be if the government would just bless a pure stored value cash card. Yes, I understand the arguments against it (mostly based on surveillance IMHO) but still it would be a useful thing in terms of getting us to 0 coins per transaction. :-) [1] Yes, I subscribe to the theory that GDP is inherently a time based numbers "value per unit time"
- andreareina 2y agoOTOH I liked that I could buy a meal with a single coin.
- ChuckMcM 2y agoThe other doesn't discuss the 'prices' vs 'currency' question which would relate to your sentiment. Recently visited Japan where they have a lot of different coins, 1, 5, 10, 20, 50, 100, 500 yen. We don't talk a lot about dollar coins, but they were there to replace the $1 bill which gets worn out. A $5 coin (like the the 5 L coin in the UK) would be the 'you can get a meal with one coin' coin.
- Const-me 2y agoIn ideal world, I would prefer coins to be powers of 2. It requires 7 coins in [ 1 .. 64 ] range to reach 100, but the average of popcnt( 1 .. 99 ) is only 3.19 coins per transaction, way better than 4.1 coins.
- IanKerr 2y agoNow account for the amount of mental overhead required for the average person to calculate change or coinage of a random amount in base two coins, as opposed to multiples of 5 or 10, and see if your 3.19 coins per transaction really saves you time.
- chipsrafferty 2y agoGreat idea! Let's also make them double in diameter and density each denomination increase.
- Jemm 2y agoCanada got rid of the penny for cash transactions. Problem solved
- icepat 2y agoAll transactions, actually. They're rounded to the nearest 0.05
- dddddaviddddd 2y ago> As pennies are gradually withdrawn from circulation, price rounding on cash transactions will be required. This will have no impact on cheque payments or electronic payments, such as credit and debit cards, only cash transactions will be affected. https://www.canada.ca/en/revenue-agency/services/forms-publications/publications/gi-131/phasing-penny.html https://www.canada.ca/en/revenue-agency/services/forms-publi... I paid $2.88 for something the other day by card. Only cash transactions (should) round.
- icepat 2y agoOdd, I distinctly remember gas prices on some machines behaving that way in 2012 or so.
- mikedelfino 2y ago> The chance you have 43 cents in your pocket is equal to the probability that you have 29 or 99 cents in your pocket (in addition to any bills). This was something I found fascinating when I first visited the US. I'm not sure if it's common across the entire country, but it definitely happened everywhere I shopped: I always received the exact change. If something cost $1.97 and I paid $2 in cash, I would get 3 cents back. And so on, no matter how many coins would be necessary. How thoughtful. I'm more used to rounding off and leaving the change behind, no questions asked.
- iconjack 2y agoI believe the young economist mentioned in the article is simply wrong in his analysis. The most efficient 4-denomination set is {1,5,18,25} (tied with {1,5,18,29}) at 3.89 coins per transaction, better than the economist's {1,3,11,38} at 4.10. This result is from a 2003 paper by Jeffrey Shallit called "What's This Country Needs is an 18¢ Piece". Just before posting, I verified Shallit's result with a Python program. [1] https://graal.ens-lyon.fr/~abenoit/algo09/coins1.pdf https://graal.ens-lyon.fr/~abenoit/algo09/coins1.pdf
- p0w3n3d 2y agoWhile European Bank is striving for cash removal the coin is a nonstarter
- TomMasz 2y agoI currently have 0 coins and 0 bills on me. I had to borrow $10 from my wife to tip the bartenders at a wedding this past Saturday since I didn't want to go to an ATM. Cash (and coins) have their place but it's not worth the effort to make them more efficient anymore.