In this essay, I argue that in the wake of the London bombings that screening passengers is still not cost effective.

I am pretty sure that any cost-benefit analysis of “equal-opportunity” screening would reach an adverse determination. Crude racial profiling would be just as bad, because terrorists would simply work around the profiles. The approach that makes the most sense to me is to search primarily on the basis of the risk characteristics of the individual, with proximity to a “potential target” only a secondary factor. Today, we do it the other way around, which is extremely cost-inefficient.

UPDATE: In my essay, I argued that bomb-detecting sensors seemed like a better idea than video cameras. I had no technical basis for this argument. But Peter Huber backs me up