Wednesday, November 24, 2010

ABC News poll on TSA scanners misleading

So, ABC news polled 514 people by telephone to try to find out if people support the new backscatter x-ray machines. They are reporting now that people support them "2 to 1" over those opposing them. However, if you look at their sampling methodology (available on a PDF on their site), you can see that they actually skewed the question. Their whole focus was on determining support _in lieu of the privacy issues_. They did not, however, include any questions about the support if there were _risks due to radiation_ They asked questions about how informed users were about possible risks, but only generically and treated it as if it was relegated to just opinion.

Here is the question they asked that the 2-to-1 figure is based on:

"The Transportation Security Administration is increasing its use of so-called
'full-body' digital x-ray machines to screen passengers in airport security lines.
(Supporters say these machines improve the ability to spot hidden weapons and
explosives, and reduce the need for physical searches.) (Opponents say these machines
invade privacy by producing x-ray images of a passenger's naked body that security
officials can see, and don't provide enough added security to justify this.) Which
comes closer to your own view - do you support or oppose using these scanners in airport security lines? "

Here is the question they asked about health concerns:

"As far as you're aware do you think these new scanning machines may pose a health
risk, or do you think that's not a serious concern?"

As if the health risks are just some kind of matter of opinion? Why not ask a question like,

"Researchers have shown that these machines emit X-rays in high enough doses that are concentrated at skin depth and may well increase the risk of cancer (skin, testicular, etc.), which will knowingly result in harming people each year -- more than the machines might save from terrorist attacks. Given this information, do you think that their usage is justified?"