The N.S.A.'s Math Problem

NYT reported News that AT&T, Verizon and BellSouth gave customer records to the National Security Agency has set off a heated debate over the intricacies of espionage law. But legal or not, this sort of spying program probably isn't worth infringing our civil liberties for — because it's very unlikely that the type of information one can glean from it will help us win the war on terrorism.

There are three things wrong with this

1. If it is not likely to help with the war on terrorism, it certainly is not going to hurt our civil liberties, because if they can't track terrorists they can't track anyone doing anything
2. Considering how much the NYT is opposed to it, why are they pointing out potential problems; could it be they are making them up
3. Considering how much the NYT seems to want to warn the terrorists how we are tracking them, could it be that this analysis is designed to tell them how to block us?

If the program is along the lines described by USA Today — with the security agency receiving complete lists of who called whom from each of the phone companies — the object is probably to collect data and draw a chart, with dots or "nodes" representing individuals and lines between nodes if one person has called another. Mathematicians who work with pictures like this are called graph theorists, and there is an entire academic field, social network analysis, that tries to determine information about a group from such a chart, like who the key players are or who the cell leaders might be. But without additional data, its reach is limited: as any mathematician will admit, even when you know everyone in the graph is a terrorist, it doesn't directly portray information about the order or hierarchy of the cell. Social network researchers look instead for graph features like "centrality": they try to identify nodes that are connected to a lot of other nodes, like spokes around the hub of a bicycle wheel. But this isn't as helpful as you might imagine. First, the "central player" — the person with the most spokes — might not be as important as the hub metaphor suggests. For example, Jafar Adibi,

With a name like that, he could easily be an arab. Is it possible he is lying to keep us from finding the terrorists.

an information scientist at the University of Southern California, analyzed e-mail traffic among Enron employees before the company collapsed. He found that if you naïvely analyzed the resulting graph, you could conclude that one of the "central" players was Ken Lay's ... secretary.

If you can identify the top man's secretary, it should be easy to find the top man