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Stock and Flow (2010)

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Re: Stock and Flow (2010)

#21

Post by jacques_chester »

foobar_ wrote: post #16
jacques_chester wrote: post #6

Earlier quoted context omitted.

There are a few startups around trying to web-ify Systems Dynamics. I've been meaning to play with Sheetless: https://sheetless.io/

That seems closed. I just came across this ... https://ncase.me/loopy/ definitely looks fun!

Oh drat, they used to have free examples you could play with. (Edit: they still have a free plan, after signup, so I still intend to try it)

I've seen Loopy before, but Sheetless looked more like existing tools with storied histories (Stella etc).

Like any forehead-smacking moron who can code I have sometimes considered writing my own because the thing I miss most of all in systems dynamics tools is being able to use git and write tests. But I know now that writing real software is really hard.

Re: Stock and Flow (2010)

#22

Post by jacques_chester »

greenshackle2 wrote: post #13
alexpetralia wrote: post #2

Relevant essay when thinking about stocks & flows in a system: http://donellameadows.org/archives/leverage-points-places-to...

I've read a lot of "system analysis" / "system dynamics" literature in grad school, and did workshops with practitioners, and my impression is that they suffer a lot from "if you have a hammer". Business people and ecologists discovered modeling with ordinary differential equations, created their own jargon and tools around it, and decided it is the key to understand everything . ODEs are a great tool to have in your…

I think it's fair to say that System Dynamics has two major strands of thinking. One grows out of the original Forrester style -- managerialist, looking for hard numbers, wanting to solve hard problems. I count Sterman in this strand; he has himself lamented that SD as a field has not kept up with developments in other fields it could adopt[1].

The second strand is more woo-ey. Meadows falls into that category. It's fun, but I don't use SD as a thinking harness because I want to be one with anything or achieve Satori. I use it because I am too stupid to solve systems of differential and integral equations merely by squinting at things.

I quite like DES as a style too. It's tremendously more efficient and easier to debug. I sorta-kinda smooshed them together in a simulator I built[0].

[0] https://github.com/pivotal/skenario

[1] "System Dynamics at Sixty" in System Dynamics Review Jan-June 2018. There are some PDFs around: https://scholar.google.com/scholar?cluster=15699150741004493...

Re: Stock and Flow (2010)

#23

Post by greenshackle2 »

jacques_chester wrote: post #22
greenshackle2 wrote: post #13

Earlier quoted context omitted.

I've read a lot of "system analysis" / "system dynamics" literature in grad school, and did workshops with practitioners, and my impression is that they suffer a lot from "if you have a hammer". Business people and ecologists discovered modeling with ordinary differential equations, created their own jargon and tools around it, and decided it is the key to understand everything . ODEs are a great tool to have in your…

I think it's fair to say that System Dynamics has two major strands of thinking. One grows out of the original Forrester style -- managerialist, looking for hard numbers, wanting to solve hard problems. I count Sterman in this strand; he has himself lamented that SD as a field has not kept up with developments in other fields it could adopt[1]. The second strand is more woo-ey. Meadows falls into that category. It's…

I think that is a fair assessment. I was studying ecology so more on the Meadows side of things.

There are definitely useful tools there, I think it's great to make use of this stuff, as long as you don't drink the kool-aid.

Re: Stock and Flow (2010)

#24

Post by 082349872349872 »

jbranchaud wrote: post #19
082349872349872 wrote: post #18

Earlier quoted context omitted.

recent discussion: https://news.ycombinator.com/item?id=23337759

I became aware of both of these articles through Tom Critchlow's writing on Digital Gardens. In this piece, he references the Garden and Stream concepts, while also adding in his own, Campfires. https://tomcritchlow.com/2018/10/10/of-gardens-and-wikis/ Then in this follow on piece, he touches on Stock and Flow referencing the original article. https://tomcritchlow.com/2019/02/17/building-digital-garden/

The "campfires" remind me of HN: more eddies than a stream, but still on the involuntarily short term side, like visiting a garden with a tour group.

Re: Stock and Flow (2010)

#25

Post by jacques_chester »

greenshackle2 wrote: post #23
jacques_chester wrote: post #22

Earlier quoted context omitted.

I think it's fair to say that System Dynamics has two major strands of thinking. One grows out of the original Forrester style -- managerialist, looking for hard numbers, wanting to solve hard problems. I count Sterman in this strand; he has himself lamented that SD as a field has not kept up with developments in other fields it could adopt[1]. The second strand is more woo-ey. Meadows falls into that category. It's…

I think that is a fair assessment. I was studying ecology so more on the Meadows side of things. There are definitely useful tools there, I think it's great to make use of this stuff, as long as you don't drink the kool-aid.

I've found it very powerful but I still like to poke my head into everyone's tents for ideas.

Re: Stock and Flow (2010)

#26

Post by jacques_chester »

foobar_ wrote: post #12
Jtsummers wrote: post #5

Earlier quoted context omitted.

You may be interested in reading more about system dynamics. There are a number of good books out there: - Thinking in Systems , also by Meadows - Business Dynamics , by Sterman (slowly working through this) - Strategic Modelling and Business Dynamics , by Morecroft - General Systems Thinking , by Weinberg (on Leanpub you can get the PDFs, it's 4 books there, as I recall the first two were published as one book when…

Awesome. Pretty much the only book I partially read on systems thinking was introduction to cybernetics by Ross Ashby. http://pespmc1.vub.ac.be/books/IntroCyb.pdf

Ashby's book is pretty decent, considering that Cybernetics as a field can feel unapproachable to lay folk. In terms of DNA, cybernetics and systems dynamics both draw deeply from the well of early control 20th-century theory and so there are some conceptual overlaps. In relative terms I think cybernetics does a better job of surfacing the contributions of information theory and system dynamics does a better job of surfacing the impact of stocks and flows on overall dynamics (as its name would suggest).
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