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What happens when you add a new teller? (2008)

johndcook.com

11–20 of 30 posts

Re: What happens when you add a new teller? (2008)

#11

What does it mean that service times are exponential?

Good question! It means that the probably of finishing in the next increment of time is always the same. Just got up to the teller? There's, say, a 20% chance that you're done within the next minute. Been at the teller's desk for 30 minutes already? Still a 20% chance that you're going to be wrapped up in the next minute.

Re: What happens when you add a new teller? (2008)

#12
post #9

Did a fun project for my MBA. A bike parking facility downtown, where you can park your bike securely, showers, lockers, towel service, ironing boards, buy some coffee and a snack. Raised $80k for it...needed 100. Anyways We modeled the showering process. Had some data on how long people took to shower. Needed something like 3 showers per gender to get good throughput One of the MBA profs didn't like this for some re…

Why gender the showers in the first place? Seems like added complication for little to no benefit by splitting into separate queues.

Re: What happens when you add a new teller? (2008)

#13
post #12
post #9

Did a fun project for my MBA. A bike parking facility downtown, where you can park your bike securely, showers, lockers, towel service, ironing boards, buy some coffee and a snack. Raised $80k for it...needed 100. Anyways We modeled the showering process. Had some data on how long people took to shower. Needed something like 3 showers per gender to get good throughput One of the MBA profs didn't like this for some re…

Why gender the showers in the first place? Seems like added complication for little to no benefit by splitting into separate queues.

I would guess the showers were inside of a gendered locker room.

If you had them as self-contained shower rooms with changing area, that would probably be better from a personal standpoint and also alleviate the issue you raised.

Not the OP though, so who knows.

Re: What happens when you add a new teller? (2008)

#14
post #8

Kind of a textbook description of queue theory if you were taking a stochastic processes class. If the author really is suggesting this for use in retail line situations, he is out of touch because... retail managers have no idea what queue theory is. If they did, they would be making much more money, and not working in retail. Staffing is more of a function of how many people you can get on the clock without getting…

Retailers do use queue theory (here's an old article about it[1]), it just has to come from the management down rather than individual store managers.

1: https://www.nytimes.com/2007/06/23/business/23checkout.html

Re: What happens when you add a new teller? (2008)

#15
post #12
post #9

Did a fun project for my MBA. A bike parking facility downtown, where you can park your bike securely, showers, lockers, towel service, ironing boards, buy some coffee and a snack. Raised $80k for it...needed 100. Anyways We modeled the showering process. Had some data on how long people took to shower. Needed something like 3 showers per gender to get good throughput One of the MBA profs didn't like this for some re…

Why gender the showers in the first place? Seems like added complication for little to no benefit by splitting into separate queues.

Yeah it really slows throughput, especially if your users aren’t 50/50 men women. There are locker room layouts that can accommodate mixed genders, like ones where each shower is in a changing stall, e.g. https://i.pinimg.com/originals/1a/ec/31/1aec3156f4f31ca42540...

Re: What happens when you add a new teller? (2008)

#16
post #12
post #9

Did a fun project for my MBA. A bike parking facility downtown, where you can park your bike securely, showers, lockers, towel service, ironing boards, buy some coffee and a snack. Raised $80k for it...needed 100. Anyways We modeled the showering process. Had some data on how long people took to shower. Needed something like 3 showers per gender to get good throughput One of the MBA profs didn't like this for some re…

Why gender the showers in the first place? Seems like added complication for little to no benefit by splitting into separate queues.

we did a survey of cyclists and gendered bathrooms were much preferred. this was 9 years ago though...

Re: What happens when you add a new teller? (2008)

#17
post #16
post #12

Earlier quoted context omitted.

Why gender the showers in the first place? Seems like added complication for little to no benefit by splitting into separate queues.

we did a survey of cyclists and gendered bathrooms were much preferred. this was 9 years ago though...

Community consultation is the right thing to do! I wonder if modelling might have predicted better service times for the majority gender with non-gendered bathrooms, and that might have swung the survey result.

Re: What happens when you add a new teller? (2008)

#19
post #4

Why I will never live anywhere with roommates, or have an event, anywhere with one bathroom!

Meh, it's not that bad. I lived my 6 years of college in a dorm with 5 people lodged in one room - 15ish m2. One bathroom in each two room duplex containing two sinks, one private toilet and one private shower. Surprisingly, it worked really well. We rarely had to que and if someone was using a part of the bathroom you could still use the rest of the facilities.

Re: What happens when you add a new teller? (2008)

#20

It's all fun and games until it's not a bank with one teller, but a LabCorp with one phlebotomist, and you're not there to give a blood sample, but a urine sample.

Or you get some one like me with uncommon tests I once had 75% of my local hospitals phlebotomist's working out how to do this particular test.
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