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Level or Simultaneous Function?

Posted: Sun Jul 14, 2019 9:15 am
by aalto-comnet
Hello!

I am receiving a simultaneous equation error due to the fact that part of my model is about modelling behavior and the loops do not involve any stocks. This can be solved either by turning one of the variables to Level or with the Simultaneous function. The thing is, which one should I choose?

Is a Level variable supposed to be only for stocks? In the link below, it is stated that Levels are also called accumulations, stocks, and states. Could it be a behavioral state as well then?

https://www.vensim.com/documentation/in ... ?21995.htm

If turning a variable into Level is not the correct approach for my model, which of the variables of my model should be turned to Auxiliary Simultaneous, with what initial value, and why?

Attached my (draft) model.

Thank you!

Re: Level or Simultaneous Function?

Posted: Mon Jul 15, 2019 12:07 pm
by Administrator
Definitely a level here. Hunger will increase with time, and decrease as a result of eating.

Re: Level or Simultaneous Function?

Posted: Mon Jul 15, 2019 2:28 pm
by aalto-comnet
Hi! Thanks for replying! So, as far as I understand, levels can be used even if we are not accumulating tangible items, right? In order to model, for example, various behavioral aspects.

Re: Level or Simultaneous Function?

Posted: Tue Jul 16, 2019 4:33 pm
by Administrator
Yes. Hunger can be treated like a level, just like say morale could be for an army.

Re: Level or Simultaneous Function?

Posted: Wed Jul 17, 2019 8:19 pm
by aalto-comnet
Thanks for clarifying! :)