Something’s fishy about these financial models

Jonah Lehrer answers the burning question of the day: what do cod fish have to do with the current financial crisis?

The [cod population] models were all wrong. The cod population never grew. By the late 1980’s, even the trawlers couldn’t find cod. It was now clear that the scientists had made some grievous errors. The fishermen hadn’t been catching 16 percent of the cod population; they had been catching 60 percent of the cod population. The models were off by a factor of four. “For the cod fishery,” write Orrin Pilkey and Linda Pilkey-Jarvis, in their excellent book Useless Arithmetic: Why Environmental Scientists Can’t Predict the Future, “as for most of earth’s surface systems, whether biological or geological, the complex interaction of huge numbers of parameters make mathematical modeling on a scale of predictive accuracy that would be useful to fishers a virtual impossibility.”

In the same way, incorrect but highly lucrative financial models caused people to take on too much risk and leverage.

• finance
• Jonah Lehrer