Originally Posted by Mientree

1. Take the amount of actual WEI found by this method and divide it by the number of passengers where the machine has alarmed and multiply by 100 for a percentage. (Effective percentage of postive test results.)
2. Take the amount of actual WEI found by this method and divide it by the total passengers tested and multiply by 100 for a percentage. (Percentage of true positive test results.)
3. Take the total direct costs of testing (equipment, swabs, personnel, etc.) and divide that by the number of actual WEI found by this method. (Average direct cost per true positive test result.)

My guesses are that 1 is small, 2 is very small, and that 3 is significantly large, especially when reviewed against 1 and 2.

My point? The cost / benefit ratios would not appear to point to this an effective test method for finding WEI - a primary goal of the administrative searches by TSA.

As all of life comes with risks, the struggle is to learn how to balance those risks against the costs and rewards. Sometimes it works out that the costs involved (ETD testing) exceed the reward (finding WEI via ETD testing) for the limited risk that is present (number of WEI found via ETD testing). The sad part is, the same could be said for the (in)effectiveness of the AIT scanners.