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Scientifically, You Are Likely In the Slowest Line
MojoKid writes "As you wait in the checkout line for the holidays, your observation is most likely correct. That other line is moving faster than yours. That's what Bill Hammack (the Engineer Guy), from the Department of Chemical and Biomolecular Engineering at the University of Illinois — Urbana proves in this video. Ironically, the most efficient set-up is to have one line feed into several cashiers. This is because if any one line slows because of an issue, the entry queue continues to have customers reach check-out optimally. However, this is also perceived by customers as the least efficient, psychologically."
That's a shame, since it's obviously the most fair, and eliminates the annoyance of jockeying into different lines to maybe get a faster one. I guess people like the chance of getting lucky occasionally, even at the cost of utility (average wait time) and fairness? Hmmm, our economy makes so much more sense now.
How is that ironic? Doesn't everyone know that? There is no customer configuration in which a single queue isn't more efficient than multiple queues, in average or worst-case waiting time or throughput. You could probably model that and prove it mathematically without needing simulation or experiments.
The mystery remains though why Fry's has upwards of 60 checkout registers when only 5 or 6 are open at any one time.
Negative moral value of force outweighs the positive value of good intentions.
The video actually says that, mathematically, you are likely (2 out of 3 times) not to be in the fastest line.
In his example of three lines, there is still a 2/3 chance that you are not in the slowest line. So unless "one in three" has become "likely," the headline demonstrates a failure at basic maths.
What's this mean? Two thirds of the time at least one neighboring line will be moving faster than you, and you'll curse and stew and froth about your terrible misfortune. But look on the bright side -- two times out of three, at least one of the neighboring queues will have exactly the same burning jealousy towards your swifter, more efficient checkout.
Ironically, the most efficient set-up is to have one line feed into several cashiers.
Alanis Morissette called; she wants her misused word back. Anyway...the above statement ain't necessarily so. What putting everyone into a single queue does is ensure that the distribution of waiting times is very narrow -- everyone will spend very nearly the same amount of time in the queue before reaching a cashier. However, this setup will almost always impair overall checkout efficiency (measured in customers per hour) by some amount; the average waiting time will be slightly longer. Each time a customer clears the cash desk and the cashier has to wait for the next customer to arrive, time is lost. Since the customer can't unpack his basket while the cashier is finishing with the previous customer, time is lost. It gets worse if a customer at the head of the queue doesn't realize that a cashier is available; everyone stands around waiting that extra bit of time. Yes, this can be offset by having a staff member playing shepherd, but that's extra expense for the store (and wouldn't it be better to have that employee actually manning a cash register?). As well, the store needs to be able to maintain a larger open space by the cash registers through which people can move, to get from the head of the queue to the checkout.
In other words, the one-queue system is less efficient in terms of staff costs, less efficient in terms of average customer waiting time, and less efficient in terms of use of floor space. The only advantage is the one alluded to -- it eliminates the slow cashier/slow customer/bad luck penalty, and ensures that everyone has roughly the same wait. (And for that, I actually do prefer this system -- but I don't pretend that it's really more effiicient. I accept that I'm paying a small premium in average waiting time - and writing off a chance to ever be in a lucky fast line - to avoid the risk of occasional long waits.)
~Idarubicin
Let's think about this a bit first. At a place like Costco, you may be trying to feed 20+ registers at a busy time. In terms of average wait time, it's better to have each line constantly full rather than to have someone have to move over to a register and start putting things up on the conveyor belt only after someone else cleared said register. One solution to this is that you specify have exactly one customer waiting behind each register, starting to load goods onto the conveyor belt. First of all, you now have the exact unfairness issue that multiple lines causes since one person might be behind someone with one item, and another behind someone with dozens of items. Might as well let them pick lines since you have the same result anyways, and don't need as much space dedicated to people forming a long line. If you still want to consider a single line, what about those far away stations (there must be at least one register 10 stations away or more)? And what if someone at one of those far away locations only has one or two items? Maybe we should switch to two customers behind each register before forming a big line? And how does a single line affect traffic in the store when you have 40+ people jamming up your main aisle on one side? Maybe we should have a line on each side? Or maybe it's best to let the customers sort through the situation, and just focus on having all open registers used to capacity, as currently is done.
FIRST... no he dose not prove that you are in the SLOWEST line. He demonstrates that it's most likely that you are NOT IN THE FASTEST LINE. The exact same argument can be used to show that you are likely NOT IN THE SLOWEST line [of course, Slashdot editors and readers have never written any kind of mathematical proof, so the concept of "similarly" is foreign to them].
SECOND... this is elementary probability... barely even high-school level.
Given 3 lines
WLOG, randomly choose one
there is 1/3 probability that your line is the fastest
therefore there is 2/3 probability that your line is not fastest
therefore it is more likely that you are not in the fastest line
THIRD... there is nothing ironic about the single queue being fastest. This is obvious to anyone who has even set next to someone who's brother's dog licked someone who accidentally clicked on the wiki page for queuing theory.
I cannot believe that this drivel got posted. Apparently, Slashdot is now for remedial math. AND the poster (and editors) didn't even get it right! Slashdot editors fail remedial math.
I know this site went to shit about 7 or 8 years ago, but all nerd cred is forever lost in my eyes. It is now just for 12 year old mouth breathers who have no idea what they are talking about.
Logging into my account that I created when I officially gave up on this website. I am not going back to routing *.slashdot.org to 0.0.0.0 so that I am never tempted to return here on a lark.
If you have 3 lines, you'd think that 2/3rds of the time there's another line which moves faster. But if you're in a slower line, you're spending more time in that line. So with three lines, you're only in the fastest line for 1/3rd of your purchases. But you're in the fastest line less than 1/3rd of the time. The way Fry's does it with a single queue is pretty much the best way (I can think of an exception for those 10 items or fewer lines).
As an English major, what I find interesting is that slashdot's grammar nazis are never one of us - the people who have studied language in detail. Rather, they're usually math and computer programmers, for whom formal systems are incredibly important. If you misuse a semicolon in a program, it can fuck shit up. But that's a program or an equation, and while they may use the same glyphs as language, they're not the same thing. Because everyone speaks English, many assume they're experts with it. But, to someone who's studied it extensively, hearing "decimate means 'reduce by 1/10' and any other usage is wrong" is the same as telling a programmer "goto isn't a word" It's taking the rules from one discipline, applying them to another, and then saying the second is in error. Spelling and grammar are important, but they're important for the same reason that dressing nicely is important. People are superficial, and will judge you by superficial things. You can't be sloppy with language and expect people to think you're smart, any more than you can dress like a slob and have people think you're professional. However, as we all know, there's times when you don't need to look professional - and that's what
grammar nazis don't understand. If I say you're an idiot for not wearing a suit to Wal-mart, you'd say I was a shallow dick. If you correct my usage of "begs the question" in anything but a formal philosophical essay, you're being just as bad. For the people who claim they're protecting the language from "degradation," take it from the English majors - language will be fine without you. There's never going to be a point where language degrades so much that we say "fuck it" and die off. Right now, there's hundreds of
different languages being spoken around the world, you think one more is going to destroy communication forever? So the idiom "I could care less" doesn't make sense when parsed
like a computer. Neither does saying "let the cat out of the bag" when you really mean "bring an issue to light." So it makes it slightly harder for a foreign student to learn
the rules, it's not like English is the only language in the world with confusing expressions. The general tone of slashdot often suggests that, because English majors don't have
a lot of job opportunities, we're dumber than scientists or engineers. We may be stupid for choosing the major, but once we've gotten our degree, we know just as much about our
field as a compsci major knows about his. I don't go around assuming that my knowledge of Qbasic lets me tell the admins how easy it is to keep the site up.
-Uncoolio
A hybrid system. Do the same thing we do at our self-checkout line, there are 2 opposing sections of 3 kiosks facing eachother across open space. One line forms (usually), and the next-in-line goes left or right depending on what register is open.
R| |R
R| |R
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So, at a Costco, have 2 registers face eacher (conveyor belts across from each other in a space 2.5 carts wide) and use those line seperators airports and banks use to make a one cart wide line leading to both (this needs to be no longer than a few feet). Then a person can choose which line to join, and then can choose whether to go left or right -- probably as they see one or the other side paying sucessfully.
Alternatively, at my Ikea, there are two registers, one right behind the other. So when a single line forms, the guy ahead of it can skip to the front register if free or it looks to be free. Same system as I described, basically.
People still can make a choice (while forced queing would piss them off even if faster), get some of the benefits of a faster line if some grandma decides to pay with a check, and won't have any of the other hassles you describe like a massive, single long line.
i pick the line with fewest women in them because they always seem to want to write a check and don't start pulling the checkbook out of their purses until after all items have been scanned... don't want to be sexist but there it is
I love the self service lines...
I hate them. Hire a damn person, clerks aren't that expensive and we have a lot of unemployment. This is not a case of automation being massively more efficient, its just penny pinching and putting people out of work. Plus whenever there is a problem, and they happen often, you have to wait for the one clerk at the kiosk to come over and correct the issue. It amounts to poor service in the name of minimal savings.
"You want to know how to help your kids? Leave them the fuck alone." -George Carlin
I love the self service lines...
I hate them.
Then don't use them. I have never seen a store where they are mandatory.
... putting people out of work.
Please educate yourself.
Wonderfully? Wonderfully??? To wander back and forth through a rats maze where the bends are NOT wide enough to granny in front of me to maneuver her cart around without knocking merchandise off the flimsy pegboards. To _finally_ get the to the head of the line and seem to be able to outguess the annoying automated voice guide. (you can see people swipe or hand over cash, the clerk has hit the total button, but the guide doesn't send you to the clerk until after they have hit the change button, even then there is an almost 2 second lag between "Please go to" and the cashier number. And yet it seems _everybody_ , even after staring dumbly at the same signs and flashing lights for 2 minutes STILL starts, looks up in surprise and peers around trying to figure out which aisle the voice is telling them to go to. (With some I suspect the problem is the voices in their head are contradicting the voice on the pole) At the end of this Skinner inspired rat's maze there isn't any frickin' cheese for the customer
This is kind of the point. Although it is more efficient to do this it pisses us off as customers because we just see one long line. We do not notice that it is moving 10 times quicker than 10 separate queues would be. It also robs us of our ability to actively get to the front faster choosing the shortest line and forces us to be more passive which is a state of mind our society does not usually encourage.
I dont read
No, it's just people being idiots. It doesn't work as sarcasm. "I couldn't care more" would work as sarcasm.
which is totally what she said