Last year, as the financial meltdown was getting underway, a scientist named Yaneer Bar-Yam developed a computer model of the economy. Instead of the individuals, companies and brokers that populate the real economy, the model used virtual actors. The computer world allowed Bar-Yam to do what regulators cannot do in real life. It allowed him to change the way actors behaved and then study how those changes rippled through a complex ecosystem.
The virtue of computational models is that when you are confronted by a dizzying array of potential problems, they can tell you where to focus your attention.
Our culture celebrates intuitive leaders who make brilliant calls -- even when we suspect their success was largely luck. Computational models, which speak the language of scientific doubt, are less sexy, but they can tell a president who takes empirical evidence seriously where public health dollars, battlefield troops and financial interventions can have the greatest impact.