Correct me if I'm wrong, but isn't 6-sigma a reference to a repeatable process that is in control but subjuect to random error of some magnitude? This is why it's applicable to the manufacturing of, say, semiconductors or turbine blades.

By definition, a true "six-sigma" program is wasted on a process such as that run by TSA (or Starwood, which has wasted untold time and money pursuing a similar program), which involves a continuum of traveling individuals passing by screening individuals.

Rather than over-complicating the issue, why don't we just insist on the TSA to make logical & effective policies, then scrupulously follow them?