5 ms·

Maximising utilisation usually means an increase in latency. You don't want your ambulances or fire fighters at high utilisation.

cogman10 6y ago
It's a balance. If 10 firefighters don't see high utilization, you don't want to increase the staff to 20, just in case. That's just a waste of money. The rule of thumb is that you want utilization to be where there is an acceptable latency depending on some percentile of cases. For a firefighter, you'd probably look at p99 latency. For a hamburger joint, p50 on order time would be good enough.
- jschveibinz 6y ago
  Great interchange of comments.
- Yeroc 6y ago
  Seems like the original article/book and your comment tie back to Little's Law from queuing theory which is used as justification in Kanban for minimizing WIP.
- ErikVandeWater 6y ago
  I doubt you will ever see even firefighters with low utilization. They can use extra time to do inspections to make sure there aren't any fires, or put on presentations at neighborhood association meetings teaching the public about fire hazards. If they aren't doing those things and there aren't any fires, they're just lazy.
  - burnished 6y ago
    Absolutely not. Not that those things aren't great, and hopefully already being done, but there is zero need to ask firefighters to be at 100% utilization at all times. There is value in having some one perform busy waiting in the event of an emergency. Did you know thats a training drill they perform? How fast they can be out and on their way from the moment of getting a call.
    - ErikVandeWater 6y ago
      > there is zero need to ask firefighters to be at 100% utilization at all times. That's why I didn't call for it.
- omginternets 6y ago
  >you don't want to increase the staff to 20, just in case. That's just a waste of money. I believe OP's point is that you do want the staff of 20, for the once-in-a-lifetime fire that requires 20 people. See also: the recent Texas power grid debacle, or the saturation of ERs due to COVID.
  - wott 6y ago
    > you do want the staff of 20 No, you don't. Resources are not infinite, and at some point the budget has to be taken from other services which are more useful than a once-in-a-lifetime event. Or you do want the staff of 20, but then it must be a volunteer and/or on-call duty system. Otherwise it is not sustainable. In my country, the shift/switch to professionalisation that started 30 years ago has gradually become a big problem. Despite the fact that they still represent only 20% of the firemen, they are killing the budgets, and they always want more (lots of strikes); apart from 'standard' raises, the most common thing they ask for, is that on-call hours should be paid full-rate, as active hours. Which, beside being extremely costly, is absurd when they are 'working' 24h shifts! It contains a few hours of training and, depending on location, a few hours of duty; the rest is on-call (at home or on premises depending on the type of station), the number of service calls is limited, and 1 in 4 shifts happen without a single call (even more for 12h shifts). There are plenty of other problems which surround this professionalisation, but they are not directly related to this subject.
    - slfnflctd 6y ago
      On-call at home should definitely pay less than active duty. That way, when a call comes in, the annoyance of being interrupted is offset by knowing you're getting paid more for responding. If you get paid the same, responding to a call just becomes an annoying interruption ("I could be at home making the same money if this person I'm helping had just been more careful!"), leading to a worse experience for everybody.
    - omginternets 6y ago
      I think we’re getting hung up on specific numbers. The general point, I think, could be summarized as: you want some idle resources to handle surge capacity. Whether that’s 5 or 20 firefighters is of course the next question.
the-dude 6y ago
In The Netherlands it is more like our IC beds.
- NotSammyHagar 6y ago
  What does ic bed mean?
  - SunlightEdge 6y ago
    Intensive care
  - deleted 6y ago
    [deleted]
  - pegasus 6y ago
    IC = Intensive Care

cogman10 6y ago

It's a balance. If 10 firefighters don't see high utilization, you don't want to increase the staff to 20, just in case. That's just a waste of money. The rule of thumb is that you want utilization to be where there is an acceptable latency depending on some percentile of cases. For a firefighter, you'd probably look at p99 latency. For a hamburger joint, p50 on order time would be good enough.

jschveibinz 6y ago
Great interchange of comments.
Yeroc 6y ago
Seems like the original article/book and your comment tie back to Little's Law from queuing theory which is used as justification in Kanban for minimizing WIP.
ErikVandeWater 6y ago
I doubt you will ever see even firefighters with low utilization. They can use extra time to do inspections to make sure there aren't any fires, or put on presentations at neighborhood association meetings teaching the public about fire hazards. If they aren't doing those things and there aren't any fires, they're just lazy.
- burnished 6y ago
  Absolutely not. Not that those things aren't great, and hopefully already being done, but there is zero need to ask firefighters to be at 100% utilization at all times. There is value in having some one perform busy waiting in the event of an emergency. Did you know thats a training drill they perform? How fast they can be out and on their way from the moment of getting a call.
  - ErikVandeWater 6y ago
    > there is zero need to ask firefighters to be at 100% utilization at all times. That's why I didn't call for it.
omginternets 6y ago
>you don't want to increase the staff to 20, just in case. That's just a waste of money. I believe OP's point is that you do want the staff of 20, for the once-in-a-lifetime fire that requires 20 people. See also: the recent Texas power grid debacle, or the saturation of ERs due to COVID.
- wott 6y ago
  > you do want the staff of 20 No, you don't. Resources are not infinite, and at some point the budget has to be taken from other services which are more useful than a once-in-a-lifetime event. Or you do want the staff of 20, but then it must be a volunteer and/or on-call duty system. Otherwise it is not sustainable. In my country, the shift/switch to professionalisation that started 30 years ago has gradually become a big problem. Despite the fact that they still represent only 20% of the firemen, they are killing the budgets, and they always want more (lots of strikes); apart from 'standard' raises, the most common thing they ask for, is that on-call hours should be paid full-rate, as active hours. Which, beside being extremely costly, is absurd when they are 'working' 24h shifts! It contains a few hours of training and, depending on location, a few hours of duty; the rest is on-call (at home or on premises depending on the type of station), the number of service calls is limited, and 1 in 4 shifts happen without a single call (even more for 12h shifts). There are plenty of other problems which surround this professionalisation, but they are not directly related to this subject.
  - slfnflctd 6y ago
    On-call at home should definitely pay less than active duty. That way, when a call comes in, the annoyance of being interrupted is offset by knowing you're getting paid more for responding. If you get paid the same, responding to a call just becomes an annoying interruption ("I could be at home making the same money if this person I'm helping had just been more careful!"), leading to a worse experience for everybody.
  - omginternets 6y ago
    I think we’re getting hung up on specific numbers. The general point, I think, could be summarized as: you want some idle resources to handle surge capacity. Whether that’s 5 or 20 firefighters is of course the next question.

the-dude 6y ago

In The Netherlands it is more like our IC beds.

NotSammyHagar 6y ago
What does ic bed mean?
- SunlightEdge 6y ago
  Intensive care
- deleted 6y ago
  [deleted]
- pegasus 6y ago
  IC = Intensive Care