During the Biden administration (2021–2024), the U.S. immigration system was under a lot of pressure. There was a record-high asylum backlog, not enough detention space, and policy changes that made more people eligible to apply, all while the system struggled to keep up. This model reflects those challenges. It shows how more and more asylum seekers were entering an already overwhelmed system, while slow processing times and uneven funding made it hard to move cases forward. As a result, detention numbers kept rising, but deportations stayed relatively low. Instead of resolving cases efficiently, the system settled into a kind of uneasy balance, leaving many people stuck in limbo, neither fully processed nor removed.

An initial study of the economics of single use coffee pods.

A simple model of economic growth where a government taxes the economy, and spends it on capital and revenue goods.

Like previous models, this model shows the operation of a simple economy, the influence of changes in the consumption rate, and the effect of government intervention. In addition, this model shows changes in the hypothetical general price level. It gives an idea of changes in price trends based on changes in the quantity of money. NOTE: No general price level exists. Prices provide information for the exchange of individual economic goods.

The statement that there can be no economic activity without  energy and that fossil fuels are finite contrasts with the fact that money is not finite and can be created by governments via their central banks at zero marginal cost whenever needed.

An important fact about COAL, GAS and OIL (especially when produced via fracking) is that their net energy ratios are falling rapidly. In other words the energy needed to extract a given quantity of fossil fuels is constantly increasing. The falling ratio 'EROI' (Energy Return on Energy Invested ) provides yet another warning that we can no longer rely on fossil fuels to power our economies. In 1940 it took the energy of only one barrel of oil to extract 100. Today the energy of 1 barrel of oil will yield only 15. We cannot wait until the ratio falls to 1/1 before we invest seriously in alternative sources of energy, because by then industrial society as we know it doday will have ceased to exist. An EROI of 1:1 means that it takes the energy of one barrel of oil to extract one barrel of oil - oil production would simply stop! 

Butterfly Effect
Sensitivity To Initial Conditions
(sensitive dependence on initial conditions)
Navier Stokes Equations
Lorenz Attractor
Chaos Theory, Disorder and Entropy



If M is the state space for the map , then  displays sensitive dependence to initial conditions if for any x in M and any δ > 0, there are y in M, with  such that

Calculating EOQ using classical inventory model

WIP SD REpresentation of Steve Keen's BOMD Minsky model (described in Fig.5 of his patreon Jan2021 Draft New Economics Manifesto) to hope to make the causal structure clearer

Based on 2023 framework from Australian Treasury mapped into the Salutogenesis framework via social wellbeing

IM-168155 Summary of Ch 27 of Mitchell Wray and Watts Textbook see IM-164967 for book overview with simplified Mike Radzicki's 2003 Evolutionary Economics history article added

Economic capital growth model, Figure 27 from Thinking in Systems by Donella H. Meadows

The World3 model is a detailed simulation of human population growth from 1900 into the future. It includes many environmental and demographic factors.

Use the sliders to experiment with the initial amount of non-renewable resources to see how these affect the simulation. Does increasing the amount of non-renewable resources (which could occur through the development of better exploration technologies) improve our future? Also, experiment with the start date of a more environmentally focused policy.

However, an unchanging doctrine may prompt actions that influence and change reality. Do ill-adapted doctrinal reactions not increase the complexity in the world, potentially making everything worse? Some Neoliberal economic remedies come to mind. 

This model shows the structure and operation of a simple economy. It can represent economic systems at different levels of abstraction (e.g. a single good, a group of goods, multiple groups, & an "economy.")

In summary, lower rates of consumption (based on production) result in higher rates of production and consumption in the long-run. Rates of consumption over 100% of production will diminish the savings stock and eventually cause rates of production and consumption to fall.

This model also shows the operation of a simple economy. It differs from Model 1 primarily in the representation of all goods in the economy by units of measure of a higher level of abstraction. Thus, the same model can represent economies at different levels.

The simulation demonstrates how differing rates of consumption affect Savings.

WIP Overview model structures of Khalid Saeed's 2014 WPI paper Jay Forrester’s Disruptive Models of Economic Behavior  See also General SD and Macroeconomics CLDs IM-168865

How education causes the gap between socio-economic status?

Goodwin business cycle model, modified from Keen and Blatt

Economic capital growth in a system constrained by a non-renewable resource, Figure 37 from Thinking in Systems by Donella H. Meadows