Why does the National Security Agency (NSA) spy on Americans? In short, it is attempting to reduce even further the small probability of terrorist attacks on Americans. That reduction in probability, times the value of the damages averted, is the expected benefit of spying. However, spying is costly in a number of ways. A numerate analysis shows that the cost of NSA spying is substantially higher than the expected benefits. NSA spying on Americans should be ended.

This is the opening paragraph of one of the two Featured Articles for January’s Econlib. It’s “NSA Surveillance: A Cost/Benefit Analysis,” by Charles L. Hooper.

Starting with some reasonable estimates of various costs and various probabilities, Hooper finds that the costs of NSA spying greatly exceed expected benefits. So, to bias the results against this initial finding, he inflates his estimate of benefits and understates his estimates of costs. Bottom line: it’s still not worth it. And he does this without even considering some costs of NSA spying, costs that he lists but does not delve into further.