Causal loop representation of Keynesian macroeconomics taken from the System Dynamics literature, specifically Henize 1972 MIT D-memo D-1717. See also Nathan Forrester's SF CLD Diagram from his PhD  IM-165714
Causal loop representation of Keynesian macroeconomics taken from the System Dynamics literature, specifically Henize 1972 MIT D-memo D-1717. See also Nathan Forrester's SF CLD Diagram from his PhD IM-165714
 Goodwin cycle  IM-2010  with debt and taxes added, modified from Steve Keen's illustration of Hyman Minsky's Financial Instability Hypothesis "stability begets instability". This can be extended by adding the Ponzi effect of borrowing for speculative investment.

Goodwin cycle IM-2010 with debt and taxes added, modified from Steve Keen's illustration of Hyman Minsky's Financial Instability Hypothesis "stability begets instability". This can be extended by adding the Ponzi effect of borrowing for speculative investment.

A simple budget planning system.  What additional complexities can you add?
A simple budget planning system.  What additional complexities can you add?
WIP based on Bill mitchell's blogs Sectoral balances are relationships among money flows during an accounting period. Where we perceive accumulations of past imbalances to be accrued is another matter....
WIP based on Bill mitchell's blogs
Sectoral balances are relationships among money flows during an accounting period. Where we perceive accumulations of past imbalances to be accrued is another matter....
Clone of Pesticide Use in Central America for Lab work        This model is an attempt to simulate what is commonly referred to as the “pesticide treadmill” in agriculture and how it played out in the cotton industry in Central America after the Second World War until around the 1990s.     The cotto
Clone of Pesticide Use in Central America for Lab work


This model is an attempt to simulate what is commonly referred to as the “pesticide treadmill” in agriculture and how it played out in the cotton industry in Central America after the Second World War until around the 1990s.

The cotton industry expanded dramatically in Central America after WW2, increasing from 20,000 hectares to 463,000 in the late 1970s. This expansion was accompanied by a huge increase in industrial pesticide application which would eventually become the downfall of the industry.

The primary pest for cotton production, bol weevil, became increasingly resistant to chemical pesticides as they were applied each year. The application of pesticides also caused new pests to appear, such as leafworms, cotton aphids and whitefly, which in turn further fuelled increased application of pesticides. 

The treadmill resulted in massive increases in pesticide applications: in the early years they were only applied a few times per season, but this application rose to up to 40 applications per season by the 1970s; accounting for over 50% of the costs of production in some regions. 

The skyrocketing costs associated with increasing pesticide use were one of the key factors that led to the dramatic decline of the cotton industry in Central America: decreasing from its peak in the 1970s to less than 100,000 hectares in the 1990s. “In its wake, economic ruin and environmental devastation were left” as once thriving towns became ghost towns, and once fertile soils were wasted, eroded and abandoned (Lappe, 1998). 

Sources: Douglas L. Murray (1994), Cultivating Crisis: The Human Cost of Pesticides in Latin America, pp35-41; Francis Moore Lappe et al (1998), World Hunger: 12 Myths, 2nd Edition, pp54-55.

54 8 months ago
Jay Forrester's "Market Growth as Influenced by Capital Investment" model as rebuilt by Eric Stiens
Jay Forrester's "Market Growth as Influenced by Capital Investment" model as rebuilt by Eric Stiens
 Regulation of resource allocation to service in response to service quality. A non-price-mediated resource allocation system. From Sterman JD Business Dynamics p172 Fig 5-27

Regulation of resource allocation to service in response to service quality. A non-price-mediated resource allocation system. From Sterman JD Business Dynamics p172 Fig 5-27

WIP  based on Where profits come from  paper  , Nathan Tankus  blog  and other historical sources
WIP  based on Where profits come from paper , Nathan Tankus blog and other historical sources
Spending by
the government   creates   its own 'financial resource' as the process of
crediting an account in the private sector takes place. This may sound like
nonsense, but in fact it is 'monetary reality'. This premise is supported by Bell
(1998; 2000) and Wray (1998a) who argue that the Treasur
Spending by the government creates its own 'financial resource' as the process of crediting an account in the private sector takes place. This may sound like nonsense, but in fact it is 'monetary reality'. This premise is supported by Bell (1998; 2000) and Wray (1998a) who argue that the Treasury does not need to collect or borrow funds in order to spend, but crates new funds as it spends.

Perhaps the following thought experiment  helps to understand how this is possible.  

If you imagine two drawers, each representing an account. The first drawer contains 100 gold coins and the second is empty. Also imagine that there are no other gold coins available at this time. Let's call the first drawer account A and the second account B. Now if you want to transfer 30 gold coins from account A to account B, you would actually first have to take the coins out of drawer A and then place them into drawer B. Account A will then necessarily have 30 coins less in it. Now imagine accounts A and B are held in a computer as electronic money. Instead of 100 gold coins, account A only contains the computer generated number '100'  and account B shows '0'. To get account B to show a balance of '30', it would now simple be necessary to change the '0' to '30' on the computer. The need to raid account A and to take '30' from the number '100' before you could credit  account B does not exist. Money is created as it is entered in B's account irrespective of whether A's account is debited before or after this process or not at
This model shows the operation of an extremely simple economy. The system produces and consumes each item (or good) at a fixed rate.  When production exceeds consumption, consumer goods accumulate in stocks. Trading may occur between actors in this system. That will not, however, affect the quantiti
This model shows the operation of an extremely simple economy. The system produces and consumes each item (or good) at a fixed rate.

When production exceeds consumption, consumer goods accumulate in stocks. Trading may occur between actors in this system. That will not, however, affect the quantities of the stocks of goods. It only affects ownership (not a concern of this model.)
This is a simplification of the Austerity vs Prosperity model in the hope that it will be easier to understand. @ LinkedIn ,  Twitter ,  YouTube
This is a simplification of the Austerity vs Prosperity model in the hope that it will be easier to understand.
WIP replication of Khalid Saeed's draft paper presented by the Economics chapter of the SD Society in Sept 2019  youtube video
WIP replication of Khalid Saeed's draft paper presented by the Economics chapter of the SD Society in Sept 2019 youtube video
Unfortunately, this model only produces the illusion of functioning, but I did manage to get it to give me the graph. However, because of the use of flows, if you change the time step to and the simulation length to anything other than the same numbers, you'll find the graph showing something that l
Unfortunately, this model only produces the illusion of functioning, but I did manage to get it to give me the graph. However, because of the use of flows, if you change the time step to and the simulation length to anything other than the same numbers, you'll find the graph showing something that looks more exponential. This is due to the function referencing itself in regards to time, so inevitably each time consumption grows it changes the outcome on the other side of the equation. Still, this is a convincing mock up. I added a "45 degree" line so that one could conceivably see (and also change) the difference made by altering the level of autonomous consumption.
 Clone of Wagdy Samir Macroeconomics work in progress  IM-901  Additions and deletions based on Robert Skidelsky's description of Keynes general THeory from his Biography Vol2 p 549 -571

Clone of Wagdy Samir Macroeconomics work in progress IM-901 Additions and deletions based on Robert Skidelsky's description of Keynes general THeory from his Biography Vol2 p 549 -571

  This model
shows the basic functioning and dynamics of a 'modern monetary system'.  The non-government
sectors, consisting of the private and foreign sectors initial y starts with
zero currency units. It is important to realize that  after creating a new currency the government
must first spend cu

This model shows the basic functioning and dynamics of a 'modern monetary system'.

The non-government sectors, consisting of the private and foreign sectors initial y starts with zero currency units. It is important to realize that  after creating a new currency the government must first spend currency units into the economy before they can be used: without currency units the private sector could not even pay taxes! A government that has its own freely floating currency can create a much money as it wants. It does not need tax receipts to finance its spending, and any money it spends into the economy above that collected in taxes represents income for the private sector. The model show that the government initially created 9 trillion money units, but spent only six trillion into the economy. The six trillion showed up as a government deficit, but also as wealth in the non-government sector.

Since the government can create as many money units as it wishes and transfer  them  to the private sector  to ensure an adequate level of demand in the in the economy,  austerity is unnecessary: money is available, though real resource may be scarce. This also shows that the government can contribute actively towards the creation of prosperity. 

Please note that this model was originally created by Gene Bellinger, IM 3206, from which this version was  cloned.


Circular equations WIP for Runy.    Added several versions of the model. Added a flow to make C increase. Added a factor to be able to change the value 0.5. 
Circular equations WIP for Runy.

Added several versions of the model. Added a flow to make C increase. Added a factor to be able to change the value 0.5. 
  Goodwin Model:   This is a basic version of the Goodwin Model based on Kaoru Yamagushi (2013),  Money and Macroeconomic Dynamics , Chapter 4.5 ( link )     Equilibrium conditions:   Labor Supply  = 100  Devation from the equilibrium conditions generates growth cycles.
Goodwin Model:
This is a basic version of the Goodwin Model based on Kaoru Yamagushi (2013), Money and Macroeconomic Dynamics, Chapter 4.5 (link)

Equilibrium conditions:
  • Labor Supply = 100
Devation from the equilibrium conditions generates growth cycles.
Irving Fisher's Debt Deflation Theory from Michael Joffe Fig. 3.4 p54  Ch3 Feedback Economics Book  with Private Credit Inflation boom added to the  bust cycles
Irving Fisher's Debt Deflation Theory from Michael Joffe Fig. 3.4 p54 Ch3 Feedback Economics Book with Private Credit Inflation boom added to the  bust cycles
From Schluter et al 2017  article  A framework for mapping and comparing behavioural theories in models of social-ecological systems COMSeS2017  video .   See also Balke and Gilbert 2014 JASSS  article  How do agents make decisions? (recommended by Kurt Kreuger U of S)
From Schluter et al 2017 article A framework for mapping and comparing behavioural theories in models of social-ecological systems COMSeS2017 video. See also Balke and Gilbert 2014 JASSS article How do agents make decisions? (recommended by Kurt Kreuger U of S)
9 2 days ago
WIP based on Bill mitchell's blogs.  Sectoral balances are relationships among money flows during an accounting period. Where we perceive accumulations of past imbalances to be accrued is another matter....
WIP based on Bill mitchell's blogs. 
Sectoral balances are relationships among money flows during an accounting period. Where we perceive accumulations of past imbalances to be accrued is another matter....
WIP Based on Steve Keen's Inaugural Kingston Lecture Youtube  video  slides models and data all at his  blog
WIP Based on Steve Keen's Inaugural Kingston Lecture Youtube video slides models and data all at his blog