OK, so what's the test, then?
What's the easy and reliable test I can administer to my staff, by which I can discover their own personal, specific tolerance levels to a given susbtance... before then applying the other easy and realible test to measure how much substance they've taken against this established tolerance level?
I don't think there's anything particularly easy about it. All contracts will have the typical verbage, 'don't come to work intoxicated' etc. But if you want to prevent it, you can't enforce it internally as all testing must be conducted through a third party company. Moreover, it's not always possible as drug testing is only allowed in the UK under limited circumstances. I.E Where drugs abuse can give rise to health and safety conditions or cause serious damage to a business.
My previous employer employs 1000s across Europe, but mostly here in the UK. When they introduced testing two years ago, it was as said conducted through a screening company (named Hampton Knight for the record.) They're basically scheduled to visit each depot periodically and upon arrival create a random list of employees to test. Outside this routine, if an employee is suspected of being under the influence, they can be instructed to withdraw from their duties and are placed under guard so to speak. This is until an unscheduled visit by the Doc arrives, and the employee is subsequently suspended until the now pending drug test results decide their fate.
In terms of reliability, well, you have to strike a balance. It might appeal to you to rule with an iron fist and adopt a zero tolerance policy. Cast out all the undesirables and be left with an elite workforce. But in practice that is not an effective measure. Take the example above, a considerable amount of the work force, depot to depot, is on something. Factories/warehouses, it's just the nature of this line of work. However, some of these individuals are actually highly experienced, loyal, hard-working dependable employees. Something not easily replaced after many years of service.
Now of course there're all sorts of ways to test for drug use. Continuing with my experience, their method involved two swabs under the tongue for 5>minutes or so. These two vials are then sent off to a lab and you only ever hear about them unless you test positive for something. So there's never any real closure to the uncertainty and you're on edge for a good two-three weeks thereafter.
Point is that these tests were definitely tailored to the needs of the business, especially with cannabis. The overwhelming majority of people who smoked weed passed, and only two failed because they were over the 'limit'. All things considered the only logically explanation for this, despite their denials, is that they had smoked right before their shift start. It was actually those that indulged in the powered varieties that did not fare so well.
Yes, and accidents can happen. Gear can turn out to be stronger than you expected, especially a new batch from a different supplier. You can mis-measure or something just as easily. Any number of things can happen, and I've known several my own self.
Either way, you're lying immobile, outright unconscious or stuck curled around the toilet as a direct result of your drug use... meanwhile there's an emergency or something going on with one of the kids for whom you're responsible, and you're thus negligent.
No argument about tolerances would matter at that point, and in seeking to mitigate or eliminate the risk of such things happening it is far easier, simpler and fairer to just ban employees from drugs.
Yes I do agree with this assessment, but only when applied to those inexperienced in its use where it could happen. If you want to continue to think otherwise that is your choice. But I will say unequivocally, a seasoned toker in is not going to suddenly keel over whatever strain their dealer has. The effects are almost immediate at this level of use so how you much you can continue inhaling is easily gauged. A newcomer or casual smoker doesn't have this ability, and can be quickly overwhelmed with noted symptoms with no options but to ride out the side effects. For lack of a better analogy, the reality of this happening is tantamount to me drinking a flask of whisky throughout my day at work.
Why would I do willingly do such a thing when I know it will impair me?