State Space Models

All state space models are written and estimated in the R programming language. The models are available here with instructions and R procedures for manipulating the models here here.

Friday, June 27, 2025

World-System (1950-2190) Stabilizing the Iranian Economy

 


In a previous post (here), I presented seven forecasts for Iran. The "best" forecast was a Business-As-Usual (BAU) forecast for infinite exponential growth into the future, a result that would probably please Iran's economic planners. It's also not realistic. The only thing that grows forever is cancer. At some point, Iran (and many other countries) will have to face the Steady-state Economy.

The graphic above shows a forecast for Iranian growth that reaches a steady state sometime after 2190. It involves a simple change to the IR_LM model. The growth parameter is simply changed from 1.01282761 to 0.98, a reduction of about 0.03%--slowing growth not economic stagnation.

Getting countries to reduce growth rates is not simple matter, as the IPCC has found when trying to control climate change. But, it is the same lesson demonstrated by the Limits to Growth models and System Theoretic considerations.

For Iran, Instability (unstable Systemic Growth) was created by the pressure to Modernize, both from the Pahlavi dynasty and from the Foreign Policy of the Kennedy Administration (Walt Rostow, one of Kennedy's Academic Brain Trust, was a strong advocate of "take-off into sustained growth" (the definition of historical instability in the Growth Component IR1) and a fundamental tenant of Modernization Theory


Notes

You can run the IR_LM model yourself (here). You can read an explanation of how the state space Dynamic Components Models (DCMs) are constructed in the Boiler Plate.

Your options for stabilizing the  IR_LM model are to (1) reduce growth rates and (2) increase feedback effects. Bootstrap confidence in intervals in the code will help you pick reasonable values for changes to the System Matrix F.

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