What is the best tool for system dynamics modeling?

Hi Tobias,

recently I've used MapSys to create some CLDs and SFDs. It is very intuitive, allows you to manipulate the diagrams to optimize their look so that the results look pretty. It also provides simulation features which I haven't tried yet.

Alternative tools are for example:

- Vensim (http://vensim.com)

- iThink (http://www.iseesystems.com/Softwares/Business/ithinkSoftware.aspx)

- iModeler (http://www.consideo.de)

Simpler online tools are now available, see for example Insightmaker http://insightmaker.com/ and Sysdea https://sysdea.com/ (I must declare an interest in the latter, so offer no judgement on any tool)

Hi tobias. I believe that PowerSim is a powerful tool for system dynamics modelling, even though it is strict with units consistency you have important functionalities such as risk and optimization analysis. Vensim is also a good tool, for sensitivity analysis, you can create parallel models to run differente scenarios.

So despite the fact that powersim is one of the best system dynamics software you may also try with vensim.

I hope this would help you.

Hello Tobias,

I agree with Kim about Insightmaker, it's a really good learning tool if you are new to system dynamics modeling.

I would also recommend TRUE, it has a good set of tutorials and is a freeware. I used it for my thesis, the learning curve is slightly steep, but I'm in love with the interface and how the output interactive model looks like.

Hope this helps.

What about Dynaplan Smia ? The founder of PowerSim moved on and formed another company several years ago. He is now developing Dynaplan Smia, see www.dynaplan.com

There is an SD tools page I maintain for the SD Society at: tools.systemdynamics.org

The other more important concern is what you plan to do in SD. CLDs? Small models? Large models? Hybrid models? Knowing that will help you to pick the tool within your budget.

I have been using SYMBOLS software using bondgraphs and am quite happy with it.

The recently published interactive eBook "Beyond Connecting the Dots" is an excellent source on simulation and modeling. Just put the title in Google and it will come up.

I agree with Alexander that Vensim is great. You can also give Goldsim a try (http://www.goldsim.com).

Anyone have experience with simantics ?  It's closer to more programming language capabilities, while maintaining the graphical modelling language of system dynamics tools www.simantics.org 

Hi Tobias

I think MATLAB/SIMULINK is also very good to implement system dynamic modeling using Lagrangian formulation or the other type of modeling.  Based on this software you can system identification based on intelligent method and implement it based on this software

Hello  Tobias,

I work exclusively in qualitative SD modelling and use Vensim. It's free for educational use.

Currently I'm trying to develop a System Dynamics Model of the risk factors in IT projects to develop a holistic risk management approach. 

Yes the basis for me is always a causal loop model of the factors derived from literature (case studies, etc.).

Thanks for the very helpful comments, I definitely will try some of the alternatives to see the differences to PowerSim :)

Tobias, I am just finishing a paper for EJOR on that very subject of holistic risk management using QPID under Vensim. I add the human agents outside of Vensim. If you would like to msg me I'll show you the draft before it's sent out. It's a series of four papers dealing with, respectively, the need to include dynamic behaviours, the need to include human agency, the knowledge  aspect, and lastly the issues of plural ontologies in risk identification. Mostly I'm concerned with CHASs (critical human activity systems) like epidemic control,, safety critical systems and such

Vensim is good because clearly you're not going to use a quantitative approach or numerical simulation, ,and  Vensim is particularly good for structural analysis (although others work, also).

I use Vensim PLE (freeware) with my students; it is downloadable from the Ventana Systems site www.vensim.com. This educational version is sufficient in the classroom:  it shares many features with Vensim Professional or Vensim DSS.  Nevertheless subscripts (vector representation of variables) are not available in Vensim PLE while they are many times necessary in larger models.  

We are using VENSIM DSS. It i the best tool we have come across for SD modeling. It has features such as "Arrays" which helps in dis-aggregation and takeing the model towards closer to Agent based modeling if neceesary. It has built-in optimizer which is quite powerful and useful of course.

Vensim DSS is indeed a great tool. Some of the other leading tools have arrays, optimization, sampling, etc. In addition some permit thousands of elements per array and get much closer to ABM than Vensim DSS. If you are making a first time purchase decision you would be remiss not to look at iThink by isee systems and Studio by Powersim AS.

You may want to look at "CONSIDEO MODLER". 

I realize that this is an old question but two more opinions:

Dynamics before detail - always!

Dynamics, then detail, then interface - always!

Using interface elements to help debug a model is a good idea. Each tool is different and has various advantages. Interfaces can take up the majority of the time spent modeling.

Be wise, plan ahead, sketch layouts.

A rule that I use is this:

Total model variables = exogenous variables + endogenous variables (the real SD) + variables that enable a nice interface + test variables.

You decide which of them to show to your customer/client/user/advisor/etc. Therefore Application = Model + Interface

Please watch the movie and read the reviews.

Hi there,

Vensim is one of the most user-friendly options you have.

the PLE version is free while the DSS version is not, although it has been recently cracked!

Best.

I realize that we are all expressing our opinions. No one can make an objective recommendation without experience with all the modeling tools. No one has done a thorough comparison. Each tool has features that are common to the system dynamics methodology and each tool has features that set it apart from the others.

Please be aware of 'success to the successful', switching costs, your objectives with respect to tool features (units, layout, naming, functions, interface capability, discrete event capability, links to other methods and tools, ...), your familiarity with the system dynamics methodology, and more.

Finally, know the problem domain and the usefulness of both the methodology, system dynamics, and the tool to your current and future problem solving tasks.

I have used the three leading tools and have an opinion too. I will not state it here. Contact me if you want that opinion.

Hello Leonhard,

why not using one of our tools to exactly figuring this out?

What are the most important priorities/goals for a system dynamic tool?

1. easy to understand and present

2. supports interconnected thinking

3. consens solution orientated

.....

.....

Joska,

I have been thinking about your suggestion for a month.

I am making an exhaustive features list.

Thanks,

Len

I think that Sysdea is extremely practical and agile (for agile modeling approach).

I can recommend Sysdea for practical business modeling. If you are new to system dynamics it is probably the best tool to actually figure out how system dynamics functions. If you are doing real world staff you will have all the applications that you need.

As a service to the community there are about 100 models in Powersim Studio format for free at my company's website.

Many can be viewed with the free Powersim Studio Express.

https://en.wikipedia.org/wiki/Comparison_of_system_dynamics_software#Table_of_system_dynamics_software

In my opinion Vensim (https://vensim.com/) is the best tool. There's a new version named Ventity (https://vensim.com/vensim-software/#ventity-bundle), which brings you more flexibility for analysis. By the way, if you are just beginning in the field, InsightMaker could be really helpful: https://insightmaker.com/

In my paper about SD and transport, we describe how to apply this tool to fleet management:

De gustibus non disputandem est –

About matters of taste there is no point in arguing.

De veritate disputandum est –

About matters of truth, dispute is fruitful.

Tool opinions are taste.

Model quality is truth.

How can we help those looking for a system dynamics tool to choose?

No single person has used all the available tools to model the same problem. It seems that the situation that each tool user is in has a big influence on their decision; e.g. student, professional, funds available, time available to learn, user community, sample models, tutorials, size of problem, tool flexibility, ... etc. There is no objectively developed list of these attributes. In this forum perhaps cost is the first criteria.

Hopefully we all have the same goal, quality modeling. Then we might ask how does a tool help me to achieve quality models? I do not believe we can answer that in this forum.

So, download what you can for free. Find model repositories, find tutorials, find user communities, find mentors. Expect to invest some time. Good luck!

For agroecosystems and environmental systems modelling, I would suggest STELLA or BERKELEY MADONNA.

I have used Vensim for my causal loop. You may want to try that.

Attached is a 2015 comparison. Please remember that we are in 2019, much has changed with all the software evaluated.

Could you please recommend some R package in addition?

Jim Duggan has done work with SD and R. Please search for his work. Since R is not an icon based language it has not been used much.

What is best for Agricultural System modelling ?

I don't think the content matters much. Most of the distinctions among the software packages are related to handling of data, calibration and interface features. So the key questions will be things like, who is your audience, how and when will the model be used, how much data, etc.?

I believe the best start is InsightMaker or Loopy. For modelling itself, Vensim still the best, maybe AnyLogic.

I like the Loopy visuals, but I think you have to be a little cautious with it: https://metasd.com/2017/03/loopy/

Hi. I read the answers. does anybody know which of the system dynamics software could have linked by PYTHON or R?

This is possible by several avenues. Vensim has a .dll that can be run from a variety of languages and applications. Vensim .mdl format can also be imported to PySD and c via SDeverywhere. I believe PySD can also do XMILE now. You can also run dynamic models directly in R - Jim Duggan is the expert on this. However, I think R is a good environment for exercising and estimating models, but a lousy one for developing them.

@Thomas Fiddaman appreciate for your information

The Powersim Studio line also has dll capability with C++. The SDK integrates simulations in custom-designed software applications using C++, VB, ASP, HTML, etc.

I agree with Thomas Fiddaman, without an icon based interface for building models you are operating as if in the 1970s.

I would recommend Anylogic:

(1) it handles SD as well as Agent-Based Modeling (ABM) and Discrete Event (DE) simulation in case you want to eventually develop hybrid models.

(2) it has a nice graphical interface for visualization.

(3) it has a free Personal Learning Edition (PLE) that is quite decent.

Elie Azar ,

The AnyLogic web site says: AnyLogic is the only tool that allows the combination of system dynamics model components with those developed using agent based and discrete event methods."

I know that Studio has discrete event capability and I believe that Stella Architect and Vensim also have some discrete capability. I have also seen an ABM model in Studio.

Ventity also has significant ABM and discrete capability, and the architecture works very naturally with ad hoc data.

Leonard Malczynski , I did not mean to say that Anylogic is the only one. I'm just speaking out of my personal experience with the software, which I used a lot for my research. I don't know (nor plan on defending) what they mention on their website :)

Elie Azar , thanks. I just want to let folks know that they should look at the entire market. I believe that over the years we have found up to 16 different 'SD' modeling tools out there. It is sometimes quite difficult to match one's needs to the software features. Then of course there are budgets, learning curves, switching costs, operating systems, etc.

Leonard Malczynski, totally agree.

I am using powersim studio software, but actually there is no best tool, every tool has it’s weakness and strength. You can also use Vensim, which is free download.

Masni Dyta Anggriani There is a free Powersim Studio too. Look for Studio Express at https://www.powersim.com/main/products-services/modeling-tools/express/. Stella Architect also has a free 30 license at https://www.iseesystems.com/store/products/trial.aspx. AnyLogic also has one at https://www.anylogic.com/downloads/personal-learning-edition-download/ Finally for Vensim go to https://vensim.com/vensim-personal-learning-edition/

Ventity is also free for academic use. https://ventity.biz/

In my opinion it is Anylogic because not only includes System Dynamics but also Discrete Event and Agent Based methods, which can be combined in agents, even agents inside other agents.

for modeling the economic assessment of new Circular Business Models with SD, is it essential to know the programming languages to run the SD model or with existing tools we can develop the interconnections and variables without needs of programming?

The majority of system dynamics models use basic algebra in their equations. Basically, + - * / and maybe ^. Most have many functions (100+) to do things from SQRT to matrix inversion to random distributions to array manipulation to lookups to selection criteria to If/Then/Else etc. If the economic assessment model is expecting more that that some tools can call external routines and/or permit the embedding of non-SD algorithms in an SD model. If you have a good idea of what you want to accomplish you can check the tool against your requirements at a vendor's website. If that doesn't work there are typically user groups for the more commonly used tools (Powersim Studio, Ventana Vensim, iseesystems Stella, Anylogic Anylogic, etc). User group members always provide help. Some tools also have SDK (software development kit) that permit a conversation between the SD tool and other tools (that is a rich area for discussion). I know a PhD candiate in economics that used results from I/O, econometrics, and GIS and embedded those equations/results into an SD model to look at the over time effects of renewable energy policy. I have also seen I/O calculations, Great Circle Distance calculations, links to Google Earth, discrete event, and some ABM embedded in an SD model.

Dear Tobias Riasanow ,

Are you really interested in how, that is, what mathematical methods does the software tool that performs the simulation use? If your answer is yes then I think you should use AnyLogic. If your answer is no, then you can use PowerSim or any other tool that does everything for you; the problem with this is that you will never know what it is really doing, which is especially evident when unexpected errors appear.

Actually what we are developing is based on the economic assessment for EVs remanufacturing and recycling with considering different variables and actors, what we need is to analyze the profitability of the Business Model we have designed for remanufacturing and recycling the EVs across 10 years. Based on the Cost benefit analysis (CBA) that we have performed for these operations we would like to economically assess the operations for each involved actors along the value chain (Dismantlers, remanufacturers with the robotized operation, recyclers and collecting centers). There are different scenarios analyzed for these BMs which each has different impacts and accordingly different costs and revenues, which is the point of analysis for our study.

I was on a team that looked at the future of the 'drive train' for vehicles. We used SD. Here is a reference Parametric analysis of technology and policy trade offs for conventional and electric light-duty vehicles, Energy Policy, Volume 46, July 2012, Pages 473-488. Also try the SD Bibliography at https://sds.memberclicks.net/bibliography

Parnia Shafinejad , I guess that each of your recycling and remanufacturing operations could be decomposed into a sequence of discret event operations, described in terms of entities, products, parts, queues, processes delays, resourced, services, etc.

If this is the case then your system could be modeled using some of classical discrete event tools (Gpss, Simscript, Arena...) or, much better, using the AnyLogic Process Modeling Library.

Please email me at jmgdurana@gmail.com if you like a more detailed answer.

I think you'd have to know more about the problem statement before choosing a discrete event simulation. If the questions are strategic and span several levels of the value chain, a DES is likely to emphasize a lot of detail that obstructs experimentation with alternative structures.

Tobias Riasanow Yes, of course. We would need a more detailed description of the problem, that's why I put, "I guess" in my answer and offered her a further contact. Still I think that if we want to make a cost benefit analysis, some processes description even if it is "roughly" we should do, because if not, what are we going to count?

Parnia Shafinejad , I am sorry to say the information I told you before maybe is not very updated to your problem, as Tobias Riasanow suggested --thanks Tobias-- since the issues of supply chain, circular economy, etc. are unfamiliar to me, as the only that I can help is based on my past experience in teaching automatic control and manufacturing systems topics. Still, I have been looking at the internet and I have found some information that could perhaps help you:

https://link.springer.com/article/10.1007/s10163-019-00945-y

Vensim or Matlab

I use VENSIM. I recently heard about the Enroad but not too sure how it works. I will be starting the class soon to learn how the Enroad works.

anylogic is short time but vensim long time than good

vensimDSS is long time most good

Powersim Studio (www.powersim.com) has a completely free version, no time limit. Look for Studio Express.

Powersim studio

Free webinar using Powersim Studio to introduce System Dynamics. https://systemdynamics.org/introduction-to-system-dynamics-modeling/