Our journalists are finally getting around to asking some of the crucial questions about the full-body scanners that I have suggested they spend time asking. See this article from Politico about accuracy rates (and why TSA thinks we shouldn't care), and also this report by AOL News about the health effects (and why TSA is not letting anyone test the machines).
And the results are not pretty: apparently, the false negative rate was 70 percent by some (rather crude) testing. You read that right, the inspectors looking at the naked body images fail to pick up 7 out of 10 objectionable items.
As with the "lie detectors" (which I discuss extensively in Chapter 4 of Numbers Rule Your World), TSA claims that they are useful for deterrence. In other words, it doesn't matter whether these scanners (or lie detectors) work or not; so long as terrorists (or criminals) believe they work, the job is done. Just maybe the terrorists are this dumb.
In the other report, TSA has not allowed anyone else to test the machine to verify the claim that the radiation emitted are in "minute doses" that have no negative impact on human health. Interestingly, the Johns Hopkins Applied Physics Laboratory was commissioned to produce a report that is being used to justify this claim although the Lab has denied that they studied human safety at all. The APL seems to get a lot of homeland security funded work. They were behind the ridiculous portable lie detector study that I also discuss in Chapter 4. And the Lab famously refused to cooperate with the NAS report on polygraphs.