7 ms·

When you design systems so "efficiently" that there is no slack, you increase their working efficiency, but also their fragility. We (in America) saw the costs

When you design systems so "efficiently" that there is no slack, you increase their working efficiency, but also their fragility. We (in America) saw the costs of this "just in time" slackless logistics in the economic reboot as we rebounded from the first waves of COVID: logjams at the ports. Good system design allows for the absorption of interstitial disruptions. There's a reason tall buildings sway in the wind; if they were so rigid that they didn't sway, they'd risk breaking when there is strong wind.

ChrisRR 4y ago
I think covid and the silicon shortage has shown us how JIT manufacturing completely falls apart if there's a delay in just one of your components.
- p0pcult 4y ago
  When I was in grad school in an analytics program a couple decades ago, JIT was all of the rage among the Ops Management professors. It was gratifying to see one of them actually apologize on social media for the problems wrought in this era by the dissemination of this kind of thinking.
- EFreethought 4y ago
  I thought everybody learned that JIT is bad after 9/11. It seems like the More Bad Advice crowd wants to keep living in a fantasy world.
  - harvey9 4y ago
    The management consultant comes in, removes slack (increases fragility) and leaves with their fee before shtf.
  - p0pcult 4y ago
    Interesting; I had not heard that. What specifically about 9/11 do you allege led to the perception that JIT is bad? Looking back, I don't see an obvious connection to either logistics or manufacturing, but I am definitely curious.
    - EFreethought 4y ago
      It was a while back, but I do remember airlines shut down. I think cargo flights got cancelled. It was not as bad as the COVID lockdowns, but at the time the changes were pretty drastic. A lot of overhead was added for security. Now you need ID to get into a lot of places you did not need before. For example: my uncle was a UPS driver, and he said before 9/11 people just saw the uniform and waved him through. Bottom line, I think 9/11 showed there was no slack capacity, and a lot of companies struggled. I guess companies just adjusted to the new reality. I do remember reading articles/web pages questioning JIT, and stating that if there was more slack capacity adjusting would have been easier, although I cannot think of any specific URLs/writers at the moment. I am just a software grunt, but I feel like I have seen a similar dynamic in every job/project I have been on. Management keeps yacking about innovation, and pushing more work on us, while dismissing the notion that more time and/or more people would make everyone's lives a lot easier.
- Throwawayaerlei 4y ago
  The problem is that the opposite of JIT can also "completely fall apart" with potentially even longer delays, plus loss of money. One thing people don't generally know is that as developed in Japan it's a quality control system. If a jig at a supplier gets out of alignment and parts made with it are out of spec and not noticed until assembly, you're better off with a feedback loop measured in hours instead of months. COVID and the silicon shortage ... I'm not even sure JIT has any relevance, one of the biggest problems in the US was car makers canceling orders when as you could easily predict from historical plague patterns the demand for cars would go up as people left cities. Demand for a whole bunch of things changed due to the secular changes in the economy like work from home, JIT's shorter feedback loop might even help with that. But chips are indeed one thing that shouldn't be done in JIT style. They inherently take a long time to make and are relatively easy to test. Toyoda was said to have changed their inventory strategy for them after the disruptions of the earthquake and tsunami. And then there are disruptions like a fire taking out a fab line, I remember this happening in Japan for embedded type chips. Unlikely any relevant inventory policy would save you from that especially if there's an increase in demand where stockpiling won't save you. The industry can't even in theory surge old nodes for which the equipment is no longer manufactured. We hear a not uncommon pattern is that they'll just suddenly stop making chips forever because they can no longer fix a critical machine.
  - supercheetah 4y ago
    Not being JIT doesn't preclude a supply chain from being fast, though. A fast, but non-JIT supply chain would probably create a lot of excess, but it might be worth it to overcome any bumps in the process.
    - p0pcult 4y ago
      If anyone knows fast it's a supercheetah.
    - Throwawayaerlei 4y ago
      As p0pcult notes you could not be better named to make such a comment. You're correct, but that still doesn't address the quality control issue for things like metal bending, unless you add intense $$$ inspection to the process. You still have X amount of inventory of items you haven't yet assembled into cars or whatever for the final test of quality. OK, for some of the upstream problems you could spend extra money to statistically pick individual items out of a designated stockpile/buffer and assemble them. But stockpiles work better for stuff that can be tested, like piles of ores and elements or at the complete opposite end chips and electronics that can be tested , and nowadays we have the transistor budgets for self-testing.
- ascagnel_ 4y ago
  If I remember right (and this may be apocryphal), even Toyota didn't go all-in on JIT manufacturing when they were pioneering it -- they put up strict guidelines (eg: suppliers had to be with in a certain distance and have multi-modal transit links) to try to make the system resilient against known possible disruptions.
InTheArena 4y ago
Logjams at the part were a combination of insane regulation, even more restrictive union contracts and lack of slack capacity. For example, there were rules around stack depth, rules about truck loading and unloading, lack of automation and the fact it was simply cheaper to leave boats stacked up. Agree on the point - we have a huge amount of fragility built into the system, and just - in - time logistics are a huge driver of that.

ChrisRR 4y ago

I think covid and the silicon shortage has shown us how JIT manufacturing completely falls apart if there's a delay in just one of your components.

p0pcult 4y ago
When I was in grad school in an analytics program a couple decades ago, JIT was all of the rage among the Ops Management professors. It was gratifying to see one of them actually apologize on social media for the problems wrought in this era by the dissemination of this kind of thinking.
EFreethought 4y ago
I thought everybody learned that JIT is bad after 9/11. It seems like the More Bad Advice crowd wants to keep living in a fantasy world.
- harvey9 4y ago
  The management consultant comes in, removes slack (increases fragility) and leaves with their fee before shtf.
- p0pcult 4y ago
  Interesting; I had not heard that. What specifically about 9/11 do you allege led to the perception that JIT is bad? Looking back, I don't see an obvious connection to either logistics or manufacturing, but I am definitely curious.
  - EFreethought 4y ago
    It was a while back, but I do remember airlines shut down. I think cargo flights got cancelled. It was not as bad as the COVID lockdowns, but at the time the changes were pretty drastic. A lot of overhead was added for security. Now you need ID to get into a lot of places you did not need before. For example: my uncle was a UPS driver, and he said before 9/11 people just saw the uniform and waved him through. Bottom line, I think 9/11 showed there was no slack capacity, and a lot of companies struggled. I guess companies just adjusted to the new reality. I do remember reading articles/web pages questioning JIT, and stating that if there was more slack capacity adjusting would have been easier, although I cannot think of any specific URLs/writers at the moment. I am just a software grunt, but I feel like I have seen a similar dynamic in every job/project I have been on. Management keeps yacking about innovation, and pushing more work on us, while dismissing the notion that more time and/or more people would make everyone's lives a lot easier.
Throwawayaerlei 4y ago
The problem is that the opposite of JIT can also "completely fall apart" with potentially even longer delays, plus loss of money. One thing people don't generally know is that as developed in Japan it's a quality control system. If a jig at a supplier gets out of alignment and parts made with it are out of spec and not noticed until assembly, you're better off with a feedback loop measured in hours instead of months. COVID and the silicon shortage ... I'm not even sure JIT has any relevance, one of the biggest problems in the US was car makers canceling orders when as you could easily predict from historical plague patterns the demand for cars would go up as people left cities. Demand for a whole bunch of things changed due to the secular changes in the economy like work from home, JIT's shorter feedback loop might even help with that. But chips are indeed one thing that shouldn't be done in JIT style. They inherently take a long time to make and are relatively easy to test. Toyoda was said to have changed their inventory strategy for them after the disruptions of the earthquake and tsunami. And then there are disruptions like a fire taking out a fab line, I remember this happening in Japan for embedded type chips. Unlikely any relevant inventory policy would save you from that especially if there's an increase in demand where stockpiling won't save you. The industry can't even in theory surge old nodes for which the equipment is no longer manufactured. We hear a not uncommon pattern is that they'll just suddenly stop making chips forever because they can no longer fix a critical machine.
- supercheetah 4y ago
  Not being JIT doesn't preclude a supply chain from being fast, though. A fast, but non-JIT supply chain would probably create a lot of excess, but it might be worth it to overcome any bumps in the process.
  - p0pcult 4y ago
    If anyone knows fast it's a supercheetah.
  - Throwawayaerlei 4y ago
    As p0pcult notes you could not be better named to make such a comment. You're correct, but that still doesn't address the quality control issue for things like metal bending, unless you add intense $$$ inspection to the process. You still have X amount of inventory of items you haven't yet assembled into cars or whatever for the final test of quality. OK, for some of the upstream problems you could spend extra money to statistically pick individual items out of a designated stockpile/buffer and assemble them. But stockpiles work better for stuff that can be tested, like piles of ores and elements or at the complete opposite end chips and electronics that can be tested , and nowadays we have the transistor budgets for self-testing.
ascagnel_ 4y ago
If I remember right (and this may be apocryphal), even Toyota didn't go all-in on JIT manufacturing when they were pioneering it -- they put up strict guidelines (eg: suppliers had to be with in a certain distance and have multi-modal transit links) to try to make the system resilient against known possible disruptions.

InTheArena 4y ago

Logjams at the part were a combination of insane regulation, even more restrictive union contracts and lack of slack capacity. For example, there were rules around stack depth, rules about truck loading and unloading, lack of automation and the fact it was simply cheaper to leave boats stacked up. Agree on the point - we have a huge amount of fragility built into the system, and just - in - time logistics are a huge driver of that.