Via Noah Schactman at Defensetech: Jeff Jonas, one of the nation’s leading data mining experts, has serious doubts about whether our government’s massive data mining projects have a remote chance of returning useful information.

One of the fundamental underpinnings of predictive data mining in the commercial sector is the use of training patterns. Corporations that study consumer behavior have millions of patterns that they can draw upon to profile their typical or ideal consumer. Even when data mining is used to seek out instances of identity and credit card fraud, this relies on models constructed using many thousands of known examples of fraud per year.

Terrorism has no similar indicia. With a relatively small number of attempts every year and only one or two major terrorist incidents every few years—each one distinct in terms of planning and execution—there are no meaningful patterns that show what behavior indicates planning or preparation for terrorism.

[…] Without patterns to use, one fallback for terrorism data mining is the idea that any anomaly may provide the basis for investigation of terrorism planning. Given a “typical” American pattern of Internet use, phone calling, doctor visits, purchases, travel, reading, and so on, perhaps all outliers merit some level of investigation. This theory is offensive to traditional American freedom, because in the United States everyone can and should be an “outlier” in some sense. More concretely, though, using data mining in this way could be worse than searching at random; terrorists could defeat it by acting as normally as possible.

Treating “anomalous” behavior as suspicious may appear scientific, but, without patterns to look for, the design of a search algorithm based on anomaly is no more likely to turn up terrorists than twisting the end of a kaleidoscope is likely to draw an image of the Mona Lisa.