Decomposing your complex AI problem: Hierarchy

Problem worlds often come with an innate hierarchy. Naturally, this may prompt the question: which level(s) of the hierarchy should be modelled? For example, the US Stock Market can be modelled as a whole or at the index level -- think, the Dow Jones, or for individual stocks. In a linear system, the way that the lower levels interact with the upper levels is "linear" or directly correlated. Take the example of an analytics system for business intelligence and reporting -- sales, inventories, etc.