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And this is why you schedule flights in the morning: there's so damn little slack in the system that if things go wrong at 10:00 AM at O'Hare, flights for the w

And this is why you schedule flights in the morning: there's so damn little slack in the system that if things go wrong at 10:00 AM at O'Hare, flights for the whole rest of the day are screwed up owing to the cascading delays. At least in the morning the airlines have had the overnight to unsnarl the previous day's mess because of the reduced revenue traffic overnight and the corresponding slack that accrues as a happy side effect. This is also why things like the healthcare system, transportation network, and postal system shouldn't be run for maximum utilization/efficiency under normal load: if there isn't any slack in the system it gets real ugly when things get squirrelly. In cases of localized disturbance, we get by on mutual aid: linemen and bucket trucks from far away respond in the aftermath of e.g. a hurricane or tornado. Likewise, fire departments from all over The greater Boston area responded to the gas explosions in the Merrimack Valley[0] and companies from even further away repositioned trucks to cover the departments that responded directly. When it's national or global scale event, you're left leaning on whatever slack was in the system. As we're all painfully aware, there hasn't been enough. The public health and healthcare systems have been doing heroic work, but if they weren't stretched so tight in the name of efficiency beforehand, there'd be less need for the heroic efforts. [0] https://en.wikipedia.org/wiki/Merrimack_Valley_gas_explosions https://en.wikipedia.org/wiki/Merrimack_Valley_gas_explosion...

Jtsummers 5y ago
> This is also why things like the healthcare system, transportation network, and postal system shouldn't be run for maximum utilization/efficiency under normal load: if there isn't any slack in the system it gets real ugly when things get squirrelly. A couple years before the pandemic, the counties neighboring mine (where I lived at the time) cut out most public medical services (mind you, these aren't free, just publicly funded, people still paid for them). There wasn't enough money for a private hospital to bother so this was a critical piece of infrastructure. They kept emergency and urgent care clinics in each county, but directed people to the other (more populated, higher income) counties like mine for many services. Last year was not a good year for those counties as people were now being shuttled 40+ miles if they needed to be treated (at a hospital) for COVID. Lean means cutting the fat, not the meat. They didn't just cut the fat and meat, they cut to the bone. This is when organizations find themselves in trouble and fail their clients/customers: eliminating things they don't think they need because they're "underutilized", only to discover later there was a sound reason to have that capability to begin with.
- selfhoster11 5y ago
  > Lean means cutting the fat, not the meat. They didn't just cut the fat and meat, they cut to the bone. I will upvote you just for coming up with this illustration. This should be useful for future reference.
knuthsat 5y ago
Yep, I started my programming career optimizing stuff (traveling salesmen, roster, schedules) and the optimizing criteria in academia is very far from reality. The effects of not having slack are disastrous. Although, the effects start showing after the optimization makes people believe they can squeeze even more work. The initial optimized schedules create more slack than handcrafted ones.
- deleted 5y ago
  [deleted]
- tsm_sf 5y ago
  The problem imho is that most places want to shed the freed labor rather than redistribute the load. Just slowing hiring a little adds burden.
nonameiguess 5y ago
Been seeing this with UPS after the Texas snow storm. Packages were canceled or delivered late, often missing parts of it, for over a month. It's an obvious problem with homebuilders, too. I keep seeing all these constructions just halt all work, sometimes for a few weeks or months, sometimes for a couple years. They seem to operate with absolutely no margin for error and run out of money really easily.
highfrequency 5y ago
The magnitude of the delayed flight effect is fairly small: flights at 3pm are only delayed by 10 mins more on average than 6am flights. https://fivethirtyeight.com/features/fly-early-arrive-on-time/ https://fivethirtyeight.com/features/fly-early-arrive-on-tim...
- thehappypm 5y ago
  The article doesn't paint quite the rosy picture: "The best time to fly is between 6 and 7 in the morning. Flights scheduled to depart in that window arrived just 8.6 minutes late on average. Flights leaving before 6, or between 7 and 8, are nearly as good. But delay times build from there. Through the rest of the morning and the afternoon, for every hour later you depart you can expect an extra minute of delays. Delay times peak at 20.7 minutes — more than twice as long as for early-morning flights — in the block between 6 and 7 p.m. They remain at 20-plus minutes through the 9 p.m. hour."
- jfim 5y ago
  It's been several years since I looked at the data, but if I remember correctly most flights actually arrive ahead of time. The median if I remember correctly is actually negative (ie. at least 50% of flights arrive ahead of time). However, this means that there's a long tail of flights that get delayed an hour or more, which brings the average up. Not a good situation to be in if one has to make a late connection during the day.
- mauvehaus 5y ago
  It's a little disappointing that 538 didn't talk about the distribution on this. I'm looking to avoid the one flight that's delayed an hour that means I miss my connection because my layover was an hour. Only 5 flights have to arrive on time to hit an average arrival delay of 10 minutes. Those are not favorable odds, as I see them. Especially if it's cutting into my vacation time.
  - cutemonster 5y ago
    Yes, missing a friend's wedding or an on site interview or ..., because no more connecting flights until same time tomorrow, with a probability 1 in 6 is pretty bad odds
marcus_holmes 5y ago
OK, but the corollary to this is that there are a fair few people sitting around doing not a lot on the taxpayer's dime. That's the visible side-effect of organisational slack (as TFA points out: the secretary spends most of her day doing nothing). There's been a lack of tolerance for that. We tend to feel that if our tax dollars are paying for someone, that someone had better be busy all day long. Politicians have made political capital from "cutting slack" in public services. We need a cultural recognition that slack is good. And I doubt that's going to happen any time soon.
- cutemonster 5y ago
  Maybe studying and getting better at one's job, during idle times Firemen have lots of idle time? I think they play floorball for example (good for them to stay fit)
  - marcus_holmes 5y ago
    good example :) though I think everyone realises that for firemen to be busier, there needs to be more fires, and that's not a good thing!
- tonyedgecombe 5y ago
  OK, but the corollary to this is that there are a fair few people sitting around doing not a lot on the taxpayer's dime. Politicians do like to turn things into moral issues, this is one of their favourites.
Quanttek 5y ago
Shortly before the Covid-19 pandemic, a highly-influential think tank (the Bertelsmann-Stiftung) suggested closing half of Germany's hospitals because of the low bed utilization and simple inefficiencies that pop up when smaller hospitals deal with less-common cases. That plan has now been effectively scrapped. The large number of ICU beds per capita has been one of the main reasons why Germany got so well through the first wave. The plan also overlooked that the main bottleneck has always been staff, who were already running with very low slack.

Jtsummers 5y ago

> This is also why things like the healthcare system, transportation network, and postal system shouldn't be run for maximum utilization/efficiency under normal load: if there isn't any slack in the system it gets real ugly when things get squirrelly. A couple years before the pandemic, the counties neighboring mine (where I lived at the time) cut out most public medical services (mind you, these aren't free, just publicly funded, people still paid for them). There wasn't enough money for a private hospital to bother so this was a critical piece of infrastructure. They kept emergency and urgent care clinics in each county, but directed people to the other (more populated, higher income) counties like mine for many services. Last year was not a good year for those counties as people were now being shuttled 40+ miles if they needed to be treated (at a hospital) for COVID. Lean means cutting the fat, not the meat. They didn't just cut the fat and meat, they cut to the bone. This is when organizations find themselves in trouble and fail their clients/customers: eliminating things they don't think they need because they're "underutilized", only to discover later there was a sound reason to have that capability to begin with.

selfhoster11 5y ago
> Lean means cutting the fat, not the meat. They didn't just cut the fat and meat, they cut to the bone. I will upvote you just for coming up with this illustration. This should be useful for future reference.

knuthsat 5y ago

Yep, I started my programming career optimizing stuff (traveling salesmen, roster, schedules) and the optimizing criteria in academia is very far from reality. The effects of not having slack are disastrous. Although, the effects start showing after the optimization makes people believe they can squeeze even more work. The initial optimized schedules create more slack than handcrafted ones.

deleted 5y ago
[deleted]
tsm_sf 5y ago
The problem imho is that most places want to shed the freed labor rather than redistribute the load. Just slowing hiring a little adds burden.

nonameiguess 5y ago

Been seeing this with UPS after the Texas snow storm. Packages were canceled or delivered late, often missing parts of it, for over a month. It's an obvious problem with homebuilders, too. I keep seeing all these constructions just halt all work, sometimes for a few weeks or months, sometimes for a couple years. They seem to operate with absolutely no margin for error and run out of money really easily.

highfrequency 5y ago

The magnitude of the delayed flight effect is fairly small: flights at 3pm are only delayed by 10 mins more on average than 6am flights. https://fivethirtyeight.com/features/fly-early-arrive-on-time/ https://fivethirtyeight.com/features/fly-early-arrive-on-tim...

thehappypm 5y ago
The article doesn't paint quite the rosy picture: "The best time to fly is between 6 and 7 in the morning. Flights scheduled to depart in that window arrived just 8.6 minutes late on average. Flights leaving before 6, or between 7 and 8, are nearly as good. But delay times build from there. Through the rest of the morning and the afternoon, for every hour later you depart you can expect an extra minute of delays. Delay times peak at 20.7 minutes — more than twice as long as for early-morning flights — in the block between 6 and 7 p.m. They remain at 20-plus minutes through the 9 p.m. hour."
jfim 5y ago
It's been several years since I looked at the data, but if I remember correctly most flights actually arrive ahead of time. The median if I remember correctly is actually negative (ie. at least 50% of flights arrive ahead of time). However, this means that there's a long tail of flights that get delayed an hour or more, which brings the average up. Not a good situation to be in if one has to make a late connection during the day.
mauvehaus 5y ago
It's a little disappointing that 538 didn't talk about the distribution on this. I'm looking to avoid the one flight that's delayed an hour that means I miss my connection because my layover was an hour. Only 5 flights have to arrive on time to hit an average arrival delay of 10 minutes. Those are not favorable odds, as I see them. Especially if it's cutting into my vacation time.
- cutemonster 5y ago
  Yes, missing a friend's wedding or an on site interview or ..., because no more connecting flights until same time tomorrow, with a probability 1 in 6 is pretty bad odds

marcus_holmes 5y ago

OK, but the corollary to this is that there are a fair few people sitting around doing not a lot on the taxpayer's dime. That's the visible side-effect of organisational slack (as TFA points out: the secretary spends most of her day doing nothing). There's been a lack of tolerance for that. We tend to feel that if our tax dollars are paying for someone, that someone had better be busy all day long. Politicians have made political capital from "cutting slack" in public services. We need a cultural recognition that slack is good. And I doubt that's going to happen any time soon.

cutemonster 5y ago
Maybe studying and getting better at one's job, during idle times Firemen have lots of idle time? I think they play floorball for example (good for them to stay fit)
- marcus_holmes 5y ago
  good example :) though I think everyone realises that for firemen to be busier, there needs to be more fires, and that's not a good thing!
tonyedgecombe 5y ago
OK, but the corollary to this is that there are a fair few people sitting around doing not a lot on the taxpayer's dime. Politicians do like to turn things into moral issues, this is one of their favourites.

Quanttek 5y ago

Shortly before the Covid-19 pandemic, a highly-influential think tank (the Bertelsmann-Stiftung) suggested closing half of Germany's hospitals because of the low bed utilization and simple inefficiencies that pop up when smaller hospitals deal with less-common cases. That plan has now been effectively scrapped. The large number of ICU beds per capita has been one of the main reasons why Germany got so well through the first wave. The plan also overlooked that the main bottleneck has always been staff, who were already running with very low slack.