Drug tests don't test for intoxication. They just test test for something that correlates somewhat with having been intoxicated sometime in the recent past.
Better is to use impairment testing. An impairment test is a test of cognitive function, alertness, reaction time, hand-eye coordination and similar objective things that actually correlate well with how well you can do your job now, instead of sometime in the past.
On top of that, impairment testing can catch when you are impaired for reasons OTHER than intoxication. If your aircraft mechanic is not fit to do maintenance on your jet that morning because last night he found his wife sleeping with his best friend, they argued all night, and she announced that morning she is getting a divorce, leaving him a tired, emotional wreck who will make mistakes left and right at work...an impairment test can catch it. A drug test cannot.
In addition, generally there is lag between drug testing and results. Impairment testing can be quick (a few minutes) and cheap so that you can do it to every employee, every day at the start of their shift.
Exactly this. Pot is probably the most common and it stays in your system for 30 days after use (probably the longest that is tested). Essentially the screen will fail a guy who smoked pot two weeks ago, but pass a guy who shot up heroin all last week. Like the polygraph test, they are deeply flawed, in this case, for testing for intoxication.
Also, imagine if drug tests failed an applicant for having a beer in the last 30 days. Like it or not, pot is replacing beer for a large portion of Americans, time to adapt.
That sounds like a much better idea; any reason this hasn't caught on as a replacement for drug testing? It opens up for a lot of good workers who'd otherwise be rejected, and it is more robust against the thing you actually care about preventing.
But what would it have to be about, for employers to consistently turn down an approach that gets them access to a bigger class of labor and better filtering for safety?
Good question, and worth investigation. While you do, please keep in mind that employers are not monolithic, but made up of lots of different humans with their own agendas. (And lots of those agendas include the objective of "cover your ass".)
There's a great book about (what might be) the general problem here: that there are many factors that keep us at a bad equilibrium, where a bunch of people would have to change at once to accomplish anything.
Here, I think it's something like, "insurers move very slowly to new systems, and until this new testing has a lot of data behind it, they won't adjust premium. to account for it being better. Furthermore, juries will continue to give punishingly big damage awards for using it, on the mistaken believe that a toker shouldn't be on the job even if he wasn't high and passed the reaction test."
Better is to use impairment testing. An impairment test is a test of cognitive function, alertness, reaction time, hand-eye coordination and similar objective things that actually correlate well with how well you can do your job now, instead of sometime in the past.
On top of that, impairment testing can catch when you are impaired for reasons OTHER than intoxication. If your aircraft mechanic is not fit to do maintenance on your jet that morning because last night he found his wife sleeping with his best friend, they argued all night, and she announced that morning she is getting a divorce, leaving him a tired, emotional wreck who will make mistakes left and right at work...an impairment test can catch it. A drug test cannot.
In addition, generally there is lag between drug testing and results. Impairment testing can be quick (a few minutes) and cheap so that you can do it to every employee, every day at the start of their shift.