In Modeling Risk, the Human Factor Was Left Out

What went wrong on Wall Street:

Today’s economic turmoil, it seems, is an implicit indictment of the arcane field of financial engineering — a blend of mathematics, statistics and computing. Its practitioners devised not only the exotic, mortgage-backed securities that proved so troublesome, but also the mathematical models of risk that suggested these securities were safe.

What happened?

The models, according to finance experts and economists, did fail to keep pace with the explosive growth in complex securities, the resulting intricate web of risk and the dimensions of the danger.

But the larger failure, they say, was human — in how the risk models were applied, understood and managed. Some respected quantitative finance analysts, or quants, as financial engineers are known, had begun pointing to warning signs years ago. But while markets were booming, the incentives on Wall Street were to keep chasing profits by trading more and more sophisticated securities, piling on more debt and making larger and larger bets.

“Innovation can be a dangerous game,” said Andrew W. Lo, an economist and professor of finance at the Sloan School of Management of the Massachusetts Institute of Technology. “The technology got ahead of our ability to use it in responsible ways.”

Read the whole thing.