The Best-Laid Schemes

Sometime in the late eighteenth century, Robert Burns drove a plough through a field mouse’s nest. He could see that the mouse had worked hard to build the nest, and he had destroyed all that work in an instant. As an apology, he wrote the poem titled, “To a Mouse, on Turning Her Up in Her Nest, With The Plough,” containing the following stanza:

But Mousie, thou are no thy-lane,
In proving foresight may be vain;
The best-laid schemes o’ mice an’ men
Gang aft agley,
An’ lea’e us nought but grief an’ pain,
For promis’d joy!”

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The Modeling Problem: Garbage In, Gospel Out

Planners by definition deal with complicated problems, and the only way to handle complicated problems is with models. Some models are computer programs. Others are simply in the heads of the people doing the planning. Either way, they are simplifications of reality.

For some purposes, simplifications can be useful. But when planning something as complicated as a national forest, urban area, or regional transportation system, planners fun up against what I call the Law of Modeling Limits:

Before a model becomes complicated enough to be useful for planning, it becomes too complicated for anyone to understand.”

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