The upper diagram shows the principal factors that have an influence on the budget deficit and indicates what needs to be done to correct it. But this is not the full story. The diagram below shows that  cutting public expenditure reduces aggregate demand and  increases unemployment. The reduction of aggregate demand  reduces  economic activity which has the effect of reducing  tax revenue.  In addition, the state has to pay out funds as there is a need for more unemployment benefit payments.   The result of these austerity measures  is often the opposite of their intended purpose: they can increase rather than decrease the budget deficit.

There is plenty of empiric evidence to show that this has happened time and time again. For instance, a report from UNCTAD (United Nations Conference on Trade and Development) found that between 1990 and 2000 in all the  cases examined where cutbacks in public spending and tax increases were used, the fiscal situation did not only not improve but worsened. Despite such repeated evidence, unfortunately calls for  austerity measures continue to be heard. 

This model is based off Meadows economic capital with reinforcing growth loop constrained by a renewable resource model.

This model attempts to illustrate a Strong Towns' perspective of municipal financing of our communities based on a development Growth Ponzi Scheme. http://www.strongtowns.org/the-growth-ponzi-scheme/ 

Ocean/atmosphere/biosphere model tuned for interactive economics-based simulations from Y2k on.

The macroeconomic ruel: SPENDING = INCOME = OUTPUT, WHICH DRIVES EMPLOYMENT is presented here in a schematic form. Output can be taken to be equivalent to  GDP. In order to maintain output it is necessary for all the income earned to be spent. If this is not the case, then companies find they have excess unsold stock on their hands and will cut back on production. This, in time, will lead to an increase in unemployment as companies need fewer employees. The shortfall in spending can be made up by any of the three sectors that contribute to total output. However, in cases where  a country has a trade deficit and where the private sector is not spending or investing enough, the only option is for the government to Net Spend i.e. to spend more than it collected in taxes causing a fiscal deficit.

Circular equations WIP for Runy.

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 sample model for class discussion modeling COVID-19 outbreaks and responses from government with the effect on the local economy.  Govt policy is dependent on reported COVID-19 cases, which in turn depend on testing rates less those who recover

I made this model to simulate how a companies revenue will change depending on the lifetime of the appliances it manufactures, in combination with the ratio of repair costs and price. It also shows the accumulation of e-waste.

Modern industrial civilisation has created massive interdependencies which define it and without which it could not function. We all depend on industrial farming to produce the food we eat, we depend on gasoline being available at the gas station,  on the availability of electricity and even on the bread supplied by the local baker. Naturally, we tend to support the institutions that supply the amenities and goods to which we have become accustomed: if we get our food from the local supermarket, it is likely that we would be opposed to it’s closure. This means that the economic system that relies on continuous growth enjoys implicit societal support and that nothing short of environmental disaster or a shortage of essential raw materials will impede it’s growing indefinitely. It is not hard to work out the consequences of this situation!

From Bill Mitchell and Warren Mosler December2018 billy blog entry  and mosler's MMT white paper (google docs) 2019. Some highly aggregated stocks and flows and boundaries introduced.See also Feb 2026 updated insight