Database Monitor Far from a Reality

The Pentagon project to find terrorists by searching the electronic records of all Americans, from credit-card transactions to medical files, has alarmed civil libertarians. The idea conjures up images of George Orwell's all-knowing Big Brother, able to peek into every corner of life, invading the privacy of anyone without check.

The project depends on a spreading technology known as data mining. Already Internet search engines such as Google use the technology to troll hundreds of millions of Web sites. And everyone who ever was asked by a credit-card company if a card had been stolen was selected for the call by data-mining programs that look for usage patterns indicating a theft.

Even a system with a 99 percent success rate would produce tens of millions of mistakes because of the size of the Pentagon's proposed database, Grossman said.

Steven Aftergood, a research analyst at the Federation of American Scientists and a critic of the plan, said it could actually end up harming the war on terrorism by diverting law enforcement resources down innumerable dead ends.