15 ms·
All clocks are 30 seconds late
- idunnoman1222 2y agoExcept analog clocks, remember those?
- jgrahamc 2y agoYes. My Casio on my wrist has a minute hand that creeps slowly from minute to minute.
- Bootvis 2y agoThe article does have a picture of an analog clock (The Big Ben) I think. The problem is not analog but showing seconds or not.
- cortesoft 2y agoDepends if the analog clock “ticks” on the minute or if it does a constant movement during the minute.
- serviceberry 2y agoNot really. A mechanical analog clock will typically have smooth motion, so 30 seconds into a minute, the minute hand will be halfway between two values. Most quartz watches with analog displays work the same. I don't know about Big Ben, but it's possible the author is wrong about that example.
- stvswn 2y agoI don't think so, because the sweeping motion of minute hand is effectively continuous rather than discrete, so there's no truncation. At 4:53:30 the minute hand will be correctly in between 4:53 and 4:54, if one (like the author) cares about such precision.
- tialaramex 2y agoTechnically Big Ben is the bell, the clock has typically been referred to as the Great Clock because that's sufficient explanation of what you meant. The tower, which like the clock is often referred to just as "Big Ben" colloquially, was formally named "Elizabeth Tower" in honour of the late Queen some years ago.
- fortran77 2y agoOn a larger analog clock, you can clearly see the minute hand progress from one minute mark to another.
- frenchie4111 2y agoWhat about ages?
- scarby2 2y agoi vote we move to the korean system where everyone gets a year older on January 1st
- grodriguez100 2y agoThat was a fun one but I think they changed it already. https://www.bbc.com/news/world-asia-66028606.amp https://www.bbc.com/news/world-asia-66028606.amp
- epcoa 2y agoThe fallacy is it’s a leap from logic to go from “average error is x” is the same as “is x late”. Seeing the exact transition is often if not more useful than minimizing average displayed error.
- hartator 2y agoInteresting take! Both of your pic examples are wrong though. That digital clock does show seconds and the London clock has its minute hand in between minute mark - showing progres between minute mark if you look closely. This is the same for all analogue clocks.
- crgk 2y agoI’m ready for the rebuttal post: “different clocks have different approaches to conveying information about seconds within a minute” which uses the same photos as examples.
- fouronnes3 2y agoNo my digital clock doesn't show seconds. As for the london one, I was actually wondering about that! I know it depends, because some analog clocks work like digital one and snap to the next minute by discrete increments.
- kevin_thibedeau 2y agoAll escapement driven clocks are discrete.
- michaelcampbell 2y agoPedantically, only above second granularities. They're continuous between second hand sweep movements at subsecond ones, no? I mean, there's no point on the watch that the second hand doesn't "hit" at some point, however small. Or am I wrong that "intermittent, jerky, continuity is still continuity"?
- DiggyJohnson 2y agoWell it depends on the interval. Taken to the limit, this would be a very nerdy way to rediscover calculus.
- donkers 2y ago
- nelsondev 2y agoPerhaps we could retitle the link, as it stands a bit click-baity. Perhaps, average error of clocks is 30 seconds higher because minutes use .floor() nor .round()
- tommi 2y agoThe whole post feels like nonsense.
- taco_emoji 2y agoIt is. It's just taking something obvious and recontextualizing in language that sounds like a Mysterious Conspiracy when it's really just a banal truth we all take for granted because all the other options make less sense. Like using tau over pi in geometry.
- benatkin 2y agoI like to think of it as TRUNC
- add-sub-mul-div 2y agoThis hall monitor mentality in every comments section is more annoying than titles ever are.
- ainiriand 2y agoSomehow I do not think that the Big Ben transitions the minute`s hand by using the floor function from Python.
- SideburnsOfDoom 2y agoBut neither is it continuous. It ticks. The mechanism might be made from iron, but a part of it is not unlike a floor function. https://en.wikipedia.org/wiki/Escapement https://en.wikipedia.org/wiki/Escapement
- philip1209 2y agoPerhaps, to be more precise, "How should clocks without a second-hand round?"
- qianli_cs 2y agoI think truncating down allows us to procrastinate a little more :)
- jakebasile 2y agoThe article is claiming that clocks that only show time truncated to a minute are off by an average of 30 seconds, which just isn't true in practice. When I say or hear 11:30, I assume it can be within 11:30:00 and 11:30:59. Humans rarely need accuracy to the second beyond this, so clocks intended to be used by humans truncate to the minute without causing problems. To say they are "late" is a real leap. I mean, you can reduce this to absurdity too. A clock truncating to seconds is off by an average of 500 milliseconds! The problem is no one cares in day to day usage which is what human readable clocks are made for.
- necovek 2y ago> When I say or hear 11:30, I assume it can be within 11:30:00 and 11:30:59. And if you cared about seconds-precision, you would assume 11:30:30, and thus your error would average the same 15s. The difference is that when you observe a minute change, you know that's exactly at zero seconds (instead of 30 — or 31 if you apply the same rounding rule to seconds). It is fair to ask a question if rounding would be more useful (nope), but the entire article is incoherent and speaks mostly of the author's confusion.
- glitchc 2y agoSo this is not about all clocks but more about all clocks that do not show seconds. In that case, sure.
- Someone 2y agoFTA: All the above clocks have one thing in common: they don't show seconds One of those clocks is Big Ben in London. http://www.bigben.freeservers.com/clocmech.html http://www.bigben.freeservers.com/clocmech.html: “Drive to the hands is by an oblique shaft which drives bevel gears positioned centrally on a gantry above the clock, with four shafts running out to each dial. Because there is no remontoire the hands on the dials advance by 2 seconds every two seconds, i.e. at every swing of the pendulum“ ⇒ if you look close enough, you can read the time at intervals of two seconds.
- keskival 2y agoIt's not really about flooring or rounding, but whether one thinks of time indices as ranges or moments. Days, as the author points out, are though of with "flooring", but more accurately it could be said that a date is thought of as a range between the times belonging to the date. Minutes one can consider as ranges or time indices. There the error comes, in switching the interpretation of a start of a duration to an actual estimate of a point of time index.
- ASalazarMX 2y agoA minute is an insignificant period for most daily tasks, so the convention "show me when the minute changes" is simple and pragmatic. If your task needs precise count of seconds, you get a clock that shows when the second changes, and now you are half a second late on average. You can keep playing with increasingly smaller time units until you conclude, like Zeno's arrow paradox, that you're always infinitely late.
- msm_ 2y agoPointless remark about myself, but I always set my phone's clock to second precision (I think this setting is hidden somewhere, or even needs a third-party app to unlock), and I am annoyed there's no way to do this on the lockscreen. How is it possible that nobody else (apparently) wants it, and it's not the Android default? Why would I want a clock that is, on average, a half minute off?
- ploynog 2y ago> Why would I want a clock that is, on average, a half minute off? Because in 99.9% of the cases I don't care about the seconds, it takes away space in the top status bar, and the constant changing of seconds in the top-left corner of the screen is distracting. And for the remaining 0.1% of cases, there is the clock app that shows seconds. What benefit do you gain in daily life by having the time down to the second? The argument "so it's not half a minute off on average" seems a bit self-referential.
- benatkin 2y agoI can imagine a 20 and a half year old in the US arguing this logic when fighting an underage drinking charge.
- chatmasta 2y agoDrivers licenses would be more accurate if they showed place of birth. Maybe the kid grows up to move to an eastern timezone and is accused of drinking a few hours early!
- hammock 2y agoI use a certain trick a lot when cooking, or timing anything with precision of a several minutes: 0) Suppose I am steaming vegetables for 8 minutes 1) I will check what time I started them (say 5:30) 2) I will forget the number of seconds that were on the clock when I started 3) I will pull the vegetables off at 5:38:30
- valbaca 2y agoI think a good part of this comes from how we often mention time: "It's half past two" is interpreted to mean: "it's at least half past two" If we round seconds, why not microseconds/etc? Ticking clocks let us know what time it is "at least" and uses the minutes :00 as the "barrier" Shifting that to :30 only causes more confusion IMO
- rantallion 2y ago> "It's half past two" is interpreted to mean: "it's at least half past two" I think most people would have no issue calling 14:28 "half past two". There's no "at least" to it, just an approximation.
- timerol 2y agoIf it was 2:27 and I asked you the time, I would be much happier with "half past two" than "quarter past two"
- ahazred8ta 2y agoThe Hunt for Red October gave us "He always goes to starboard in the bottom half of the hour."
- jtbayly 2y agoI can get behind this idea, however, this sentence is wrong: "If clocks rounded to the nearest minute instead of truncating, the average error would be 0.” The negative and the positive error don’t cancel each other out. They are both error. The absolute value needs to be used.
- fouronnes3 2y agoThat's a very fair nitpick, but even with a more rigorous error function the point still stands, I think.
- jtbayly 2y agoAgreed. There will be less error, just not zero. I thought it was a silly error that detracted from the point, rather than defeated the point.
- Straw 2y agoThe average error is in fact 0! The average absolute error is reduced but not 0.
- jtbayly 2y agoThat may technically be correct, but it is incorrect in the real world. I submit that error is error in the real world. Mathematics can go jump off a cliff unless it wants to be helpful. :)
- roywiggins 2y agoZero average error conveys something important though: the error that there is, isn't biased positive or negative.
- pkilgore 2y agoThat's language failing us, not maths :-)
- 2y ago
- jjslocum3 2y agoPlenty of nitpicking here, for me this piece was a fun and clever thought-ride.
- TimTheTinker 2y agoThis blog post is a really good argument. The kicker for me was that we all generally switch to rounding when asked for the hour (without minutes) but don't round when asked for the minute (without seconds). That's an inconsistency for which there doesn't seem to be a good reason. However, this inconsistency only exists orally. When a device displays the time, it never rounds. Changing the convention would probably be very confusing for a lot of people, at least initially. For now, I'm convinced that when communicating the minute orally, I should round to the nearest minute, just like I do with hours.
- necovek 2y agoVerbally, IME, people mostly round to quarters of an hour (exact hour, quarter past, half past, quarter to). I've never heard anyone say it's 4pm when it was 3.31pm.
- Ukv 2y agoI don't think this applies to Elizabeth Tower/Big Ben, as it's an analogue clock and, from footage I can find[0], its minute hand appears to move continuously opposed to in steps. (or at least, not in full-minute steps) Also, I believe it's wrong to say "the average error would be 0" if rounding to nearest minute. The average offset would be 0, but the average error would be 15, to my understanding. [0]: https://www.youtube.com/watch?v=eUP3DsiqkzA https://www.youtube.com/watch?v=eUP3DsiqkzA
- fouronnes3 2y agoThat's a good point, I was actually wondering about that. I've seen a lot of jumping analog clocks so I incorrectly assumed Big Ben was the same. I should have checked :)
- tim333 2y agoThe jumping ones are mostly electrically activated. Big Ben from 1854 is gloriously mechanical - some of the mechanism: https://www.youtube.com/watch?v=G-WSzdAF8b8 https://www.youtube.com/watch?v=G-WSzdAF8b8 pendulum https://youtu.be/U8gkgWoFBAw https://youtu.be/U8gkgWoFBAw guy who winds it https://youtu.be/dMT-OOrLBik https://youtu.be/dMT-OOrLBik
- taco_emoji 2y ago> Hours: That's when mentally, I switch to rounding! At 15:48 I definitely feel like it's pretty much 16:00. Disagree. I would never round to a full hour, only to nearest 5 minutes. As far as minutes, for clocks that show discrete minutes, it'd be weird to see the minute-hand snap to the next number and think "oh, it's actually 29 seconds before that number". Seeing the snap motion means you're at :00 seconds. Besides, for a clock that doesn't show seconds, it really doesn't matter. If you need more precision, you just use a timepiece with the extra precision.
- CharlesW 2y agoBy this logic, the author must also tell people it's "2024" until July 3, and that we're still in the 20th Century until 2051.
- monktastic1 2y agoNo, if you read the article, you'll see that he addresses this point.
- lupire 2y agoIt's addressed by "I'm not so sure."
- gkfasdfasdf 2y agoI don't think rounding clocks would be any more useful in the scenario about mentally calculating how many minutes until the meeting at noon, because a rounding clock would show noon 30 seconds earlier, so the average difference between 11:55 and noon in a rounded clock vs a floor clock is still 4.5 minutes.
- encom 2y ago>Please someone tell me I'm not crazy No, it's probably just autism.
- jsnell 2y ago> This is especially apparent when you're trying to calculate "how much time until my next meeting?", and your next meeting is at noon. If it's 11:55, you would usually mentally subtract and conclude: the meeting is in 5 minutes. That's how I always do it myself anyway! But the most probable estimate given the available information is actually 4'30"! Ok. But what does it mean for a meeting to start at 12:00 when people don't have clocks that will accurately show 12:00? They'll only know when the time is 11:59:30 or 12:00:30, anything between is just going to be a guess. So it seems to me that the start times would just align to the half-minute offsets instead, and we'd be back exactly where we started but with more complexity.
- xattt 2y agoAll broadcast studios are equipped with master clocks that show seconds to deal with this ambiguity. You can look at your own watch and anticipate when program transitions in radio or TV are supposed to take place (usually the minute and 30 second marks). Also, get a sense when a host is filling time to get to the transition.
- dylan604 2y agoI've done a lot of work with hosts on various shows. One guy stood out more than others on being so natural on the vamp/stretch to fill the time. Starting at 5mins, we give one minute signals. Not once did it ever sound unnatural in trying to rush or filled with ums, uhs, or ahs. Others struggled with the rushing being most noticeable.
- tavavex 2y ago> It would be weird if we rounded for years, months and days, that's for sure. I think most people think of those scales as intervals. In other words, July is a period of time, with a start and an end. So are years, centuries, seasons. We are inside of it or outside. I feel like my sense of time is different from the author's. While it can be useful to round the current hour/minute on some occasions, the information about which exact segment of the day/hour you're in can also be very useful. I can certainly tell that I ask the question of "when exactly is it going to be 12:00?" far more often than "how many seconds have statistically likely elapsed in the current minute?" The biggest issue for me is that the precise moment of when one minute/hour transitions into the next is important for people. Like, when coordinating an event or meeting, would you prefer it if your clock indicated the precise moment when 12:59:59 becomes 13:00:00 and told you to start the meeting, or would it be better if the clock instead told you that it was "13ish" and you'd have to wait out ~30 seconds by counting in your head? This also causes a jarring discontinuity - now clocks with a ticking hour hand appear to run 30 seconds late than clocks without, turning on the digital clock setting to show seconds offsets it, and so on. Some people celebrate New Year's or occasions that happen at a specific time 30 seconds early because they no longer have a strong reference point.
- 1832 2y agoI agree this is an interesting take and fun to think about. But if clocks rounded to the nearest minute instead of truncating, the average error would be still be greater than 0 I think, and not 0, as the author claims. Assuming a sufficiently large number of measurements taken at random times, I think the average error would be 15 seconds.
- timerol 2y agoThe author meant "average error" in the systematic error sense, not the standard error sense. The minute display would be well calibrated, not precise to less than a minute.
- johnea 2y agoAnother perfect example of wasted disk space and bandwidth on the internet 8-/ Not to mention a waste of the one truely nonrenewable resource, our time...
- daggersandscars 2y agoWhile most analog clocks' minute hands sweep from minute to minute, jumping minute clocks have the issue the article brings up. Depending on when / where you went to school, you may have had analog jumping minute clocks. The ones we had at one school would "give away" when the minute would change because the minute hand would move slightly counterclockwise before changing to the next minute.[0] Per reddit, some Swiss Railway clocks had jumping minutes, but I have not seen one in person. [1] Another school I attended had sweep second and minute hands, but would hold the clock at 59 seconds until it matched the master clock. Depending on the particular clock and how well it was maintained, these could be 5 - 10 seconds off. Seems like nothing as an adult, but as a kid wanting to go home, it seemed like an eternity, especially on the last day of class for the semester. [0] This video shows how clocks worked at my school: https://www.youtube.com/watch?v=jpU_lG_TPP4 https://www.youtube.com/watch?v=jpU_lG_TPP4 [1] https://www.reddit.com/r/clocks/comments/10714a1/hard_time_finding_a_wall_clock_with_a_jumping/ https://www.reddit.com/r/clocks/comments/10714a1/hard_time_f...
- mglz 2y agoHä?! A clock shows the period of time we are currently in. A clock only showing hours would for example indicate that we are in the 14th hour of the day, for the entire duration of that hour. That is not an error. Similarly, a hh:mm clock will show the hour and minute we are currently in for the duration of that minute. No clock can display the exact current moment of time. That would require infinite digits, and even then those will be late, since lightspeed will ensure you recieve the femtoseconds and below really late.
- cess11 2y agoWhat time it is, is just made up, it's something we can decide freely through social power, as evidenced by timezones and daylight savings and leap seconds. Commonly the resolution is something like minutes or a few of them, that's the margin we'll typically accept for starting meetings or precision in public transport like buses. The utility of femtoseconds in deciding what time it is seems pretty slim.
- v4vvdq 2y agoAn analog clock does show the exact current moment of time (if the hands move in a linear motion and don't jump).
- kypro 2y agoYeah, I think labelling it "error" is a bit of a strange way to look at it to be honest. It's only error if you're trying to measure time in seconds, but are doing it with a clock that can only measure hours and minutes. If you want to know the current minute, then a clock that can measure minutes it is 100% correct. It's an interesting thought experiment, but really all it's saying is that half of the time 10:00 is closer to 10:01:00 than 10:00:00, but this imply you care about measuring time to the second which prompts the question why it's being measured in minutes? To be charitable, I suppose in the real world we might occasionally care about how close 10:00 is to 10:01 in seconds, but the time shown on phones can't tell us that so on average we will be about 30 seconds out.
- HarHarVeryFunny 2y agoI'd be very surprised if a smartphone, syncing itself to a reference, is ignoring seconds. Why would it? To me, if a clock that doesn't display seconds is displaying 09:30, then I assume the time could be anywhere between 09:30:00 and 09:30:59. Presumably when setting the time on a device that doesn't display seconds, the seconds are being reset to 0 (i.e. setting time to 09:30 is setting it to 09:30:00), so if someone really cares about sub-minute accuracy they can take this into account.
- bena 2y agoAll this does is move when the issue he claims exists presents itself. If we flip the minute display at the 30, then the same problem occurs because if you start timing from the 20, the minute will change in ten seconds. This article is just kind of stupid masquerading as smart.
- fathertime24 2y ago[dead]
- ajb 2y ago"It's just a convention" This is correct. In fact, in one sense our clocks could be argued to be minutes out, on average: originally time was measured by the sun. But by the sun, the earth doesn't rotate in exactly the same time each day during the year. So a clock assuming each day is the same length (like they all do) accumulates an error with respect to sun time of more than 16 minutes,and then loses it again, in a cycle. But we just collectively decided that it was simpler not to bother with that. We changed the convention so that time is marked with respect to an average day length
- youainti 2y agoClocks are used as inputs into decisions. So this doesn't matter as long as the decision process accounts for it. If I see that a meeting starts in 5 minutes, I'm not setting a timer get there in 300 seconds, I'm trying to decide if I have time to fill my water bottle on the way or not. The post is a useful consideration to think if you are trying to do precise tasks though. See Keskival's post below about intervals vs moments to add some more precise ways of thinking.
- macleginn 2y agoThis is nitpicking, but the transition from "the average error of a truncating clock is 30 seconds" to "therefore all clocks are 30 seconds late!" is seriously wrong. For one, the median is equal to the mean here, so about half of all clocks are less than 30 seconds late, which is a clear contradiction.
- taeric 2y agoAmusingly, one of my kids gets very frustrated with how I answer what time it is on most requests. Most of my answers will be of what the nearest relevant time is. I will never bother determining what the exact minute is from my watch. As I just can't see the value of that. Even from a digital watch, I don't see the need in giving a majorly different answer to the same question within 5 minutes or so.
- lxgr 2y agoThat's how people commonly give time in my language, I suspect mainly out of convenience: Quarter hour precision is possible to achieve with at most five syllables (and typically just two); compare that to minute-level precision, which usually takes at least 5 and sometimes as many as 10. Interestingly, spoken times also commonly use the 12 hour clock, while times are almost exclusively written as 23 hours.
- bschwindHN 2y agoI was always annoyed at my parents for doing this when I was a kid. When anyone asks me the time I always read out the minutes for whatever time my phone shows me. Maybe someone wants to make a particular bus or train and the more precise timing is appreciated, who knows!
- 1718627440 2y agoI would same, that at is communicated by the length of the stare you get after telling the time.
- jpm_sd 2y agoTime Cube redux? https://en.wikipedia.org/wiki/Time_Cube https://en.wikipedia.org/wiki/Time_Cube
- edgarvaldes 2y agoIf you use round instead of floor an error persists. So all clocks that don't show seconds are always wrong.
- Phrodo_00 2y ago> Is it the same for the current minute of the current hour ? I'm not so sure. Yes it is. Appointments start at the beginning of the minute, not the average. (And while changing clocks WOULD change that, I'm not sure it makes a lot of sense)
- necovek 2y agoIf you do care about what second it is, you can still be 59s off: eg. if the "rounded" clock shows 12:30, it could be 12:29:30 all the way to 12:30:29. The error is reduced on average if you only care how far away from exact minute you are, but you simultaneously never know when it is the exact minute. The question is really about what's more generally useful: the offset of 30s is usually not important enough, which is why most clocks only show hours and minutes. Where it matters, higher precision is used. Some of the social constructs would be less meaningful (like New Year countdown) as most watches and clocks would show midnight 30s early.
- opan 2y agoI enable seconds on my PC and phone clocks, and basically anywhere it's an option. I enjoy seeing if two messages on IRC were just 3 seconds apart as it will often tell you the second person hasn't actually read the first person's message right before theirs (they were probably writing their messages at the same time). Something not obvious if you just see the minutes.
- jordansmithnz 2y agoWhile interesting this is just… wrong. Imagine a world where: - I tell people I’m 50 years old but I’m really just 49 1/2 - My phone says it’s Jan 7th but it’s really afternoon on Jan 6th - My coworker says they’re a sr engineer because they’ve been told that they’ll definitely be promoted soon Rounding shouldn’t be applied everywhere. Some things in life are supposed to use a floor function; common sense applies and most folks intuitively know that 1:00pm means ‘between 1:00 and 1:01pm’.
- timerol 2y agoTFA goes into the author's opinion around when to floor and when to round, and notes that "hours" is the largest interval where rounding feels right.
- err4nt 2y agoA delightful read, though I disagree. Unless we were going to introduce half-minute units (which decreases the scale of the error, but makes it twice as numerous) then shifting our minute units by a half value doesn't seem to actually solve the problem, doesn't it only shift it to a slightly different location?
- seanalltogether 2y agoYou said it yourself, the data is truncated. We shouldn't be rounding time one way or the other, just truncating it.
- deleted 2y ago[deleted]
- syntheticnature 2y agoWorse yet, our calendars are all 12 hours off!
- hkon 2y agoI show seconds in windows clock
- dsubburam 2y agoThe intended interpretation for clocks IMO is "we are now past this time". Like a mile marker when you are running down a jogging track. It doesn't matter if the granularity is one-day or even one-year, like the ball drop in Times Square on New Year's Eve.
- PeterCorless 2y agoAnyone who has done timer or countdown-based work has to think the opposite. Whether that's sports or event production, rocket launches, or so on. You're not thinking about the time you've past/expended. You're thinking of the time you still have left. "Two minutes left in game." "We're live in 30 seconds" etc.
- hnuser123456 2y agoAll of this is made redundant by just... knowing this is how clocks work. If you don't have a seconds hand/counter, you can't predict how many seconds are left in the current minute. If it's 11:45:01, it's 11:45 without seconds. If it's 11:45:59, it's still inside the minute-long interval known to everyone as 11:45. The clock can always be one second away from flipping to the next minute. I just mentally subtract one minute if I'm actually planning on being somewhere down to the fraction of a minute, and planning what I can do beforehand. Mentally subtracting 30 seconds is not any easier. I don't see this as even having some kind of gimmicky benefit...
- rkagerer 2y agoLet me unlock your hidden precision. The writer makes an implicit assumption you just glance at the clock with no prior info. Where seconds count, you can watch the clock until the moment it ticks. At that time you have greater precision. And due to your own innate sense of time, that precision decays for a little while (maybe even 30s?) rather than instantly disappearing. I like to synchronize my clocks this way (when seconds are unavailable). Yes, it does mean I invest up to a minute more to set the time, and it's probably not worth it if you're doing so often (eg. area prone to power outages).
- matja 2y agoThe same technique is how computer RTCs are set/read, but to sub-second precision instead of minute precision, because the most common register standard allows only storing whole seconds but they keep relatively accurate time.
- GuB-42 2y agoFlooring makes more sense in every case, from years to milliseconds and more. A few reasons: You want to send a message at exactly 13:00:00, you have a digital clock that doesn't show seconds. What you do is that you watch your clock, and as soon as it goes from 12:59 to 13:00, you press the button. That's also how you set the time precisely by hand. With rounding, that would be 12:59:30, who wants to send a message at precisely 12:59:30 ? You have a meeting at 13:00:00, you watch the clock to see if you are early or late. With flooring, if you see 13:00, you know you are late. With rounding, you are not sure. It is common for digital clocks to have big numbers for hours and minutes and small numbers for seconds. If you are not interested in seconds, you can look quickly from afar and you have your usual, floored time. If you want to be precise, you look closer and get your seconds. Rounding the minutes would be wrong, because it wouldn't match the time with seconds. And you don't want clocks with a small display for seconds you may not even see to show a different time than those that don't. And if you just want to know the approximate time and don't care about being precise to the second, then rounding up or down doesn't really matter.
- TZubiri 2y agoBut if every clock was like that, then 12:59:30 would be the new 13:00:00
- taylorbuley 2y agoThis is true across other domains! If trains are spaced exactly 10 minutes apart and you arrive at a random time, the expected waiting time is 5 minutes, for example.
- timerol 2y agoThis makes me wonder how train countdown clocks are programmed, and if "1 minute away" means "60-120 seconds away" or "30-90 seconds away".
- zazaulola 2y agoHas anyone ever wondered why in the US the week starts on Sunday, but in Europe and Asia it starts on Monday?
- Ylpertnodi 2y agoI work in Europe...my week starts on a Sunday.
- lxgr 2y agoWhere in Europe is that?
- lxgr 2y agoYes, and it's infuriating if software draws the conclusion that, simply because I happen to be in region x (or even worse, using language x), I must also want date presentation, units of temperature and distance etc. to be according to customs in x. At least macOS/iOS at this point mostly allow customizing many of these, but some native apps and date picker widgets still don't respect my preferences, driving me nuts every time I have to schedule a reminder or meeting.
- hinkley 2y agoThis could be a good allegory for sampling intervals. I’m forever having to explain to people that if they are looking at data every 60 seconds they can take a lot longer to notice a problem than common sense would suggest. Your new information shows up on average 30 seconds late and up to 59.99999 seconds late. If you’re trying to compare the last two samples to detect a problem then you’re going to see it up to 2 minutes after it already started, since it could start 1 ms after the first sample. Particularly in systems where multiple actors are using periodic actions.
- jerlam 2y agoI had a watchface on my Pebble smartwatch that only displayed time in five-minute intervals. This post is making me question whether it rounded up or not. I have to assume it did because I didn't start being late for everything. In case you want to see it: https://pebblestyle.com/watchface/BVmexStjq3j/ https://pebblestyle.com/watchface/BVmexStjq3j/
- deleted 2y ago[deleted]
- TZubiri 2y ago"It would be weird if we rounded for years, months and days, that's for sure. " We round years too, otherwise I would be in my 30s.
- Apes 2y agoRMSE of current digital clocks rounding down is roughly 34.5 seconds. RMSE of proposed rounding to closest is 17.5 seconds. The new method is roughly 17 seconds more accurate on average. Does this reduced error make a significant difference? Probably not. There are very annoying practical issues with this proposal though. Rounding down makes it clear what minute has already passed. If your clock says 3:00, you know the current time is definitely some point after 3:00. If something needs to happen at 3:00, and your clock says 3:00, it is time to start. With this proposed method, 3:00 could mean anywhere from 2:29:30 to 3:00:30. When do you start? Do you start as soon as your clock says 3:00? Then you're starting 30 seconds early. Do you wait until your clock says 3:01? Then you're starting 30 seconds late. And how do you set a clock that uses this scheme? If I want to set the clock to 3:00, do I wait until 2:59:30 and then set the clock to 3:00? The headaches that arise from this scheme are not worth the trivial error reduction.
- bux93 2y agoGreat example of the pitfalls of RMSE.
- ss64 2y agoAny clock which doesn't have a seconds display is probably not accurate to the second and is also very unlikely to have been set to the exact second. Those 2 factors together mean a good chance the time is > 30 seconds out, making the original point moot.
- codewritero 2y agoAnalog clocks mostly don't have the problem the author is complaining about since most minute hands move once per second and you can easily see (depending on your eyesight and distance to the clock) that the minute is partially consumed. I agree though that this is a downside to digital clocks which don't show seconds, though whether the best fix is to round instead of averaging is hard to say.
- ifdefdebug 2y agoWhile you could argue that it's flooring, it feels much more like truncating. We have a inner representation of time that's like yyyymmdd-hhmmss-mmmm and we truncate it to the precision we need for a given task. If we need the month we truncate to yyyymm, and if we need hours we truncate to yyyymmdd-hh. That's quit intuitive for all kind of time precision, and the author's rounding solution would be somewhat counterintuitive, at least for me.
- vikingerik 2y agoYup. I have my clocks in the house set 30 seconds ahead to counteract exactly this.
- lxgr 2y ago> Basically I'm arguing that rounding for clocks would be more useful than flooring. This is especially apparent when you're trying to calculate "how much time until my next meeting?" Yet a rounding clock provides no way at all for you to know whether the meeting has already started or not. Not sure where I've heard this, but an idea that's been stuck in my head is this: We don't look at clocks to see what time it is, we do so to know what time it isn't yet: Have I missed the bus yet? Can I already go home? Am I late for this meeting? Do I still have time to cancel this cronjob? All questions that a rounded clock cannot precisely answer.
- seanhunter 2y agoThose are all questions no clock can answer though. They require state from the physical world over and above knowing the current time. It’s a wild misconception to think that a flooring clock is somehow more late than a rounding clock and it’s if anything an even more crazy misconception to think that a clock can tell you whether something in the physical world has or hasn’t happened.
- layer8 2y agoThis is why I dislike clocks without seconds.
- _yb2s 2y agoI am really annoyed that it is almost universal to show only minutes on clocks- when so much in my life at least depends on knowing time to the second. Even modern digital devices like an iPhone make it really hard to get a seconds readout, when the cost of doing so should be zero. Some of the things I need precise seconds for frequently in my daily life: buying tickets to concerts, campsites, and kids camps before they sell out, checking into Southwest flights, sailboat race starts, and starting/joining virtual meetings I am hosting. Am I that weird that this is something I need at least once a day that nobody else seems to need or want?
- stackghost 2y agoAlmost nothing in my life or career to date has depended on knowing time to the second. Why does it matter if your noon meeting starts at 11:59 or 12:01?
- _yb2s 2y agoIt’s wasteful of other peoples time to show up to a meeting late, and wasteful of my own to be early. I’d like to be as precise as practical. Meetings filled with high paid experts are incredibly expensive- one should get every detail right to save time. One little thing might not matter, but if you pay attention to a lot of little details in running a meeting efficiently- including starting as close to on time as you can, it saves a lot of time.
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- intellectualx 2y agoAll the way to the miliseconds I strongly disagree!
- pmg101 2y agoI definitely start saying I'm $age+1 as I approach that birthday, as it seems more accurate. Round, not floor. Although I have to say I've not really encountered other people doing this.
- inasio 2y agoOne often unappreciated and amazing thing about the GPS-on-cellphones era is that nowadays everyone has the exact time. Up to the late 20th century it wasn't trivial to have the right time, in fact there was a three digit phone number you could call to get the right time (up to the minute).
- yu3zhou4 2y agoI thought about it as a kid, you're definitely not crazy Victor, and I appreciate that you wrote this piece
- smokedetector1 2y agoI'm not trying to be snarky but I really don't see why this matters. It's just a convention. We are not robots, not everything has to be 100% precise.
- garbagepatch 2y agoOnly robots floor, humans truncate.
- stackghost 2y agoTFA fatally misunderstands what clocks actually measure. They measure the amount of time that has elapsed. When we say "it's quarter after noon" what we really mean is that 12 hours and 15 minutes have elapsed since 00:00. The reason clocks don't round up is because that's simply wrong. A minute hasn't elapsed at xx:xx:36, it has only elapsed after :59 tl;dr The author of TFA doesn't actually understand what clocks measure.
- o999 2y agoDoes OP realize that people don't looks at 11:55 and think it means 11:55:00, but they think, it is just not 11:56 yet. Computers and smart devices syncing to NTP doesn't have 30s average error rate, it is the author who has 30s average error rate in clock-reading if he reads a digital clock and think that the clock tells that no seconds has passed since the last time it added one minute.
- layman51 2y agoThis post is fascinating but I think it is more mundane than I realized. I thought everyone knew that when a cheap digital kitchen timer shows a time like “0 H 1 M”, that actually means you have exactly 60 seconds or fewer for its alarm to go off. I might be wrong, but there was a Prince of Persia game (maybe for Game Boy?) that had the same timer behavior. It would show the time remaining to complete the level in minutes and would jump immediately from “1 minute” to 0. The iOS podcast app is more sophisticated than that. It normally displays how many minutes remain in the playing podcast episode. But what is cool is that at the 30 second boundary, it will decrease one minute. For example, it is at -24:30 or -24:29 that it will go from saying “25 minutes remaining” to “24 minutes remaining.” Then when 30 seconds are left, it is nice enough to show you a countdown of the seconds.
- fouronnes3 2y agoYeah, I've seen a lot of countdown UIs that incorrectly start beeping as soon as "1s" becomes "0s". In fact they should start beeping exaclty 1 second after that change. I'm sure this is actually an intentional design decision because starting to beep at 0.99 (displayed 0) feels more correct, even though it isn't.
- pkilgore 2y agoFun scissor. Seems to depend on your personal definition of "error", with respect to time.
- ccppurcell 2y agoI would argue that eg 13:00 represents an interval, not a moment. So there is no error. But I appreciate the nerdy level of detail.
- raldi 2y agoThis is like asserting that all calendars are 12 hours late.
- gamblor956 2y agoThis author is either an idiot or does not understand the concept of precision. It's very surprising that this article has engendered so much discussion...in support of what he is saying. 10:01:01 and 10:01:59 are both still 10:01, because a minute is a discrete unit of time. Rounding the minute to the next minute is simply wrong. Similarly, rounding to the next hour is also wrong and nobody does this except apparently the author. (Note: 15:48 is almost 1600 but is not 1600.) People might round to the nearest five or ten minutes for convenience (i.e., when reading an analog clock) but that hasn't been a thing since the switch to digital clocks.
- tech_ken 2y agoOne wrinkle here is the choice of signed error instead of eg. RMSE; absolute error metrics don't care about rounding vs. flooring. Since the conclusion of the analysis hinges on this choice of error metric, I think some justification or discussion of that choice adds interesting context. Signed error implies that clock-imprecision "cancels"; that being 20 seconds late to your meeting will be undone by being 20 seconds early to lunch afterwards. I'm not sure if this is quite how people reason about 'lateness' though. Obviously in some applications it makes sense (ex. recording event times of some phenomenon of interest), but in scheduling my daily life that's not really how I think about things. I think RMSE is closer to how people evaluate scheduling of stuff; it doesn't matter if I'm late or early, both will have notable consequences in unique ways. The ambivalence of the RMSE error to rounding vs. flooring is the intuition I would put behind the counterargument fielded by the author: > But this is just a convention! Truncating, rounding or even ceiling are all valid, as long as we pick one and stick to it. I think you can also squeeze some juice out of playing with the error metric further. If you want a 'just-in-time' schedule (ie. you want to never be early to anything) then the flooring clock is superior to the rounding clock. If you want the opposite then a ceiling-ing clock would be the best choice. > Personally, I would never say that it's 10 if the clock shows anything past 10:30 I like to floor my times to the nearest 15-minute interval (10, quarter-past, half-past, quarter-to), only rounding once I've reached ~10:55
- panda-giddiness 2y ago> If it's 11:55, you would usually mentally subtract and conclude: the meeting is in 5 minutes. But the most probable estimate given the available information is actually 4'30"! Admittedly I'm being a bit pedantic, but this isn't true. The expectation value might be 4'30", but the time is as likely to be 4'59" as 4'30"; assuming it's 4'30" will simply minimize your expected error.
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- geor9e 2y agoI have about a dozen of the absolute cheapest digital clocks around my house, and every single one, I set it to the next integer minute then waited for 00s to hit the button that makes the : blink. So, even if every other person on earth fails to do this, the average is below 30s just due to me.
- iainmerrick 2y agoThe Clock app in iOS works like this in timer mode. If you start a timer for 10 seconds, you'll see the 10 for half a second, then 9 through 1 for a second each, then 0 for half a second, then it beeps. In practice it's pretty stupid and not really useful, so I wish they'd fix it. There's a reason why normal countdowns work the way they do. You care about the exact moment it hits zero, and with rounding you lose that. Clocks are not 30 seconds late.
- zombiwoof 2y agoWhat a waste of 30 seconds of my life reading that
- thedanbob 2y agoIf you had two rounding digital clocks, one with seconds and one without, they would switch to the next minute 29.5 seconds apart. Everyone would hate that.
- jillesvangurp 2y agoBecause it would be incorrect. Like the article's main premise. Flooring is the only correct behavior for minutes. And other time units. Big Ben may not show seconds but people would notice if it started bonging 30 seconds early or late with new year. Which would be the case if it rounded. It bongs right on time. That kind of is the point. The news doesn't start half a minute early or late either. And people joining meetings after the minute changes in their clock are technically a few seconds late.
- devit 2y agoThat's only the case if you interpret them as HH:MM:00. The issue is fixed if you interpret them as HH:MM:30 instead.
- chkaloon 2y agoI also thought it was interesting when basketball essentially added 1 second to each game by including tenths on the game clock
- yellowapple 2y agoOne can speculate that current clocks are already rounding to the nearest minute instead of truncating, i.e. already accounting for this, relative to some hypothetical clock that's 30 seconds slower.
- dredmorbius 2y agoTime intervals aren't floors or rounds but thresholds. This is most evident above the level of hours, minutes, or seconds: we speak of a new day beginning (though the time at which this occurs has varied culturally and regionally), or a new year, decade, century, or millennium (with their own threshold arguments courtesy the AWOL Year Nil in the Julian/Gregorian calendrical system). Birthdates are an interesting example. In Western/European cultures, it's typical to count by full years elapsed, such that an infant within its first 12 months is 0 years old. In Asian cultures, the age is given as "1", which is reflected in an occasionally-used Western notion of "being in my nth year". That is, a 49 year old is in their 50th year. What a clock (or calendar) indicates generally is what time period you are presently in, that is, the second of a minute, the minute of an hour, the hour of a day, day of a month, etc., etc. And what's relevant from this point of view is that the threshold is what matters. The other problem touched on in this essay is of estimating time remaining to a future threshold, and here, rounding is indeed useful. If you have a 10am meeting and the time presently reads 9:55 am, you have fewer than five minutes to arrive punctually. But that is planning and not timekeeping issue, strictly.
- kuon 2y agoNow I need to extrapolate this to explain why I am 10-30minutes late every time.
- smcameron 2y agoJust sitting here with my mechanical automatic watch like some kind of renaissance fair re-enactor. Probably off by a few seconds, but probably less than 30.
- snowwrestler 2y agoA clock is not showing you what time it is, a clock is showing you what time it most recently was. It is marking time, not embodying time.
- garbagepatch 2y agoSummer starts at the solstice, when the day is the longest. But by then half the length of the season already passed with the day approaching that point. So I think the seasons are half a season off (seasonal lag notwithstanding).
- kwar13 2y agoWhat a nonsensical article. I could've used the 30 seconds I skimmed it back.
- zemnmez 2y agoI apologise for my "but, actually...": Analogue clocks like the face of big ben are not like digital displays, and whether they "show seconds" in the context of the meaning of this article is not, like digital displays, down to whether there is a dedicated hand. Unlike digital displays, the largest denomination hand on an analogue clock display contains all of the information that the smaller hands do (depending on the movement in some cases). The easiest way to realise this is to imagine a clock without the minute hand. Can you tell when it's half-past the hour? You can. The hour hand is half way between the two hours. Again, it depends on the movement, but it is not out of the question that your minute hand is moving once every second, and not every minute. It is down to the number of beats per unit time for an analogue display as to what the minimum display resolution is (regardless of if the movement is analogue or digital itself).
- deaddodo 2y agoYou literally just defined the difference between digital (binary) and analog (gradation). A digital clock is 1:01 or 1:02. An analog clock is some tick of some range (depending on the resolution, as you abstracted), at all times.
- lelandbatey 2y agoI think a slightly better term is "discrete" vs "continuous". Some analog clocks are discrete, some are continuous. Some digital clocks operate on a resolution so fine that they appear to move continuously. It's quite lovely to find those that invert your expectations when out in the real world.
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- deaddodo 2y agoYou're correct, thanks for the clarification. I was going more with the colloquial understanding of the two (analog = continuous; digital = discrete) and was trying to touch on the vagueness of no true analog clock with the reference to ticks/resolution. However, your explanation is definitely much better.
- harrall 2y agoIf I actually have to be on time and it says 11:55, I’m not going to wait 5 minutes. I would wait 4 minutes. If it’s more fluid, then 5 minutes is a fine estimation. OP’s suggestion of rounding the minutes wouldn’t change anything except make what I’m doing complex.
- moi2388 2y agoWe don’t floor clocks, we usually put them up on the wall..
- veltas 2y agoSmart enough to make the proposition, but not smart enough to disprove it. Middling intelligence might be the greatest threat to society.
- Galanwe 2y agoCenturies are also 50 years late on average... And everyone is on average 6 months older than they say. Also moving the rounding 1 place down doesn't solve anything. Now your second-resolution clock is on average 500ms late unless you move the decimal 1 place down again.
- joestrong 2y agoA slightly related thing I think about someone's, is if I look at the time and it's 13:05 and then I do a task and when I finish a task it's 13:10, you could say that took 5 minutes, but because we can't see the seconds each time could be up to a minute out. So a total of 2 minutes error! Quite big if you're timing something small like 5 minutes!
- sukmaagung 2y agoInteresting, When I make word clock, I make it change from "SATU LEBIH DUA" ("ONE PLUS TWO", 01:02:00) to "SATU LEBIH TIGA" ("ONE PLUS THREE", 01:03:00) at 01:02:30. But if I make digital clock, I make it change from 01:02 to 01:03 at 01:03:00.
- ijidak 2y agoUnrelated, but I've always wanted a clock that is randomly fast so that I never know exactly how fast it is. At worst, maybe I can set a maximum "fastness" setting. Then peeking at the actual time has minimal value over the long run. I'm sure this already exists. But I haven't come across it yet.
- riwsky 2y agoThat’s a bit of a cup half-empty way to think about it, innit
- eviks 2y agoAll universal statements like this are wrong and stem from basic ignorance > So when it's actually 14:15:45, they'll show 14:15. And when the actual time goes from 14:15:59 to 14:16:00, then that's when your clock changes from 14:15 to 14:16. No, that's a silly mistake, look at the picture (though much better - video) of the analogue clock to see it's not the case, the minutes hand moves continuously, so isn't at 15 at 15:59 > the meeting is in 5 minutes. That's not the only question we ask about time. Has the meeting/game already started? You can't answer that with an average value > for some context appropriate reason) you reply with just hours, you would say it's 11! No, you reply would depend on the context, which you haven't specified. > Please someone tell me I'm not crazy Of course not, just trying to replace one ambiguity with another. Maybe instead come up with a more precise minutes display in digital clocks that adds more info like two dots flashing when it's past 30 sec and only 1 dot when it's before? (In phones you could use color or a few more pixels within all the padding?)
- animuchan 2y agoYup, I think the "has the {thing} already started" is, for many people, the most useful function of precise time anyway. All sorts of work and personal meetings, transportation schedules, doctor's appointments, and so on. Knowing the ballpark in the form of "it's 15:30-ish", even if more precise, is strictly less useful than "you're late to the 15:30 meeting with your manager". Fun article nonetheless, and interesting perspectives on both sides!
- verzali 2y ago> All universal statements like this are wrong and stem from basic ignorance
- zelphirkalt 2y agoNot all analog clocks continuously move the minute pointer. In train stations I often see the seconds pointer move continuously and when it reaches the 12, it stops there for a second or two, then the minute pointer moves, stopping at the next minute, briefly vibrating, then the seconds pointer moves on.
- 2y ago
- atoav 2y agoThe argument is a bit like saying decimals are wrong because the one in "10" jumps to one after you counted to 9, which is 90% of the range and not 50%. But that is the point of using multiple digits. Similarily the point of using multiple units of time is that each of the parts is in it self correct. 15:30 always means it is after the 15th hour and after the 30th minute. If you want to know it more precisely you either wait till the minute changes or you get a clock with seconds. With the proposed system you would not know if the time is before or after the 30th minute. Also: why stop at the minute? You could also round the hour.. But that would introduce a weird jump and the minute would suddenly be negative 30.
- TomK32 2y agoMy computer's clock say "twenty five past ten" and I don't even take offense about the missing "-" in twenty five. It's close enough for me.
- nmeofthestate 2y ago> It would be weird if we rounded for years, months and days, that's for sure ... > Is it the same for the current minute of the current hour ? > I'm not so sure. I'm sure - it's the same.
- randallsquared 2y ago> If it's 11:55, you would usually mentally subtract and conclude: the meeting is in 5 minutes. That's how I always do it myself anyway! But the most probable estimate given the available information is actually 4'30"! But if you want to say it's M minutes, then it's either 4 or 5, and 4:30 rounds to 5, so it all works out once more! :)
- imdsm 2y agoI enjoyed this article for it's tongue-in-cheek approach. Thanks Victor!
- agentkilo 2y agoWell I was bothered by a similar problem when tweaking my StumpWM modeline long time ago. I wanted to show the seconds in the clock on my modeline, but the modeline has a fixed refresh rate, which I set to 1HZ. Then I realized my clock can never be accurate. Eventually I chose to hide the seconds to stop myself from having those nightmares, but I think they are coming back after reading this article.
- briffid 2y agoPeople are usually interested in the transients.
- bilsbie 2y agoSide note. I’m more bothered by this issue on digital thermostats. I don’t even know if they’re flooring or rounding. And sometimes half a degree makes all the difference. I do wish they’d do temperatures out to one decimal point.
- pvtmert 2y agoClocks show the time that is _passed/past_, that's the point. Hence flooring is correct approach. Even when you involve physics, you are seeing the nanosecond past. Not the actual time. (The time that takes light to travel from clock to your eyes, then your brain's processing delay via neurons etc.) Even the thought of being late is the same way. If something starts at 13:00 and you are not already there when it is 13:00:00.000, you are -by definition- late.
- Aurelius108 2y agoGood point, when you look at your watch your thought should be “3:15 has passed” or “3:15:40 has passed”. One is more precise but if you think of it as a time that has already passed you can budget accordingly. 3:15 tells you that 3:15:00 has definitely passed and as much as 3:15:59 might have passed.
- buro9 2y agoIt's been 2025 for 6 months already...
- Zobat 2y agoThis article tries to redefine the correct time by pointing to clocks that are not precise.
- turnsout 2y agoWow, I’ve never read a wronger take in my life, and that’s saying something!
- turnsout 2y agoLike even flat earth is more reasonable than this
- sam_goody 2y agoThere was a clock on HN a while ago (which I cannot now find) - it has one mode in which the clock only updates itself every random number of seconds, or ticks at different times within each second, oor ticks according to a MIDI tune as well as it can while staying within 30 seconds of the real time. So, while you can just set your clock forward 30 seconds and be done with it, there are some variations that someone who likes thinking about this are worth playing with. [My favorite mode of the referenced clock, sets the clock randomly ahead between 1-5 min. Since you don't know how much your clock is off by, you have to assume your clock is on time, and that will give you an average 2.5 minutes to actually show up on time.]
- calini 2y agoI'm sorry, you are crazy.
- deleted 2y ago[deleted]
- chikere232 2y agoThis would be an overengineered version of "I set my watch early so I'm not late" except that they argue that all watches should be set early, making it fundamentally pointless 12:00 meetings now start at 11:59:30 and you're still late Get a seconds precision watch if you care about seconds level accuracy
- magic_smoke_ee 2y agoAll dumb, manual, HH:MM clocks, that is, unless the setter had patience and used a minute-crossing boundary to synchronize, reducing the error to ~1 second and resets them frequently to not drift more than a maximum of say 10 seconds. Most dumb clocks are likely to have an error of a minute or more because of cumulative drift and few people correct them until they are wildly wrong, say 5 minutes or more. Or eschew the entire class of problem of daylight savings and drift with a GNSS- or radio time beacon-controlled clock.