But all the tools in the world are useless if we lack the imagination needed to build the right models. Models are built to answer specific questions. When a theorist builds a model, it is an attempt to highlight the features of the world the theorist believes are the most important for the question at hand. For example, a map is a model of the real world, and sometimes I want a road map to help me find my way to my destination, but other times I might need a map showing crop production, or a map showing underground pipes and electrical lines. It all depends on the question I want to answer. If we try to make one map that answers every possible question we could ever ask of maps, it would be so cluttered with detail it would be useless, so we necessarily abstract from real world detail in order to highlight the essential elements needed to answer the question we have posed. The same is true for macroeconomic models.I may have to use that in class.
Friday, August 7, 2009
Mark Thoma on Economic Models
A map has always been a principles-level analogy for why models are useful. Mark Thoma gives us a nice twist on it: