System analysis techniques applied to the Forrester world model—Part III: Correlation and spectral analysis

Correlation analysis reveals some of the inherent properties of the world system. Natural resources and capital investment form an independent subsystem and are unaffected by other state variables. Population is stable and will not increase unless forced to do so by capital investment. Spectral analysis is not particularly revealing except for the fact that a large amplitude occurs around ƒ = ƒ₀. This indicates a very inertial system and the need for more study to aid in understanding long-term changes in world behavior.