] Security is always a trade-off: How much security am I
] getting, and what am I giving up to get it? These
] "data-mining" programs are not very effective.
] Identifiable future terrorists are rare, and innocents
] are common. No matter what patterns you're looking for,
] far more innocents will match the patterns than
] terrorists because innocents vastly outnumber terrorists.
] So many that you might as well not bother. And that
] assumes that you even can predict terrorist patterns.

Schneier takes an admittedly unacademic swipe at TIA/CAPPS programs. Basically the idea is that profiling doesn't work regardless of how much data you are looking at. Proving this, unfortunately, requires a TIA project.

Newsday.com - Terror Profiles By Computers Are Ineffective