I think that the TSA should examine a study by the US Customs Service. I don't have time at the moment, but I need to look on LexisNexis. This was before 9/11, so things may have changed.

Customs found that inspecting bags at random was not effective. They discontinued random baggage searches and focused their efforts merely on those bags that aroused suspicion.

I also tend to observe the principles of screening used in the detection of diseases. Epidemiological principles argue that a screening technique can be rendered useless if it is used TOO MUCH. Why? Too many false positives divert attention away from the actual threat of disease.

Furthermore, the current "all-or-nothing" secondary screening makes little sense to me. If a passenger is wearing "suspicious shoes," why not just look at the shoes? What's the point of a pat down, inspecting his or her baggage, rifling through his wallet, and so on? It seems that the screener is so busy following too many steps dictated in the secondary screening; his or her attention is then pulled away from the item of interest.

This all seems like common sense to me, but the TSA is not a common-sense, scientific organization