The primary method of drug testing is the urine test, but this is a terribly blunt tool.
Favoured because it's quick and low cost, it tests for the metabolites of drugs rather than the chemicals themselves and as such it fails to differentiate between on- and off-the-clock use. That means occasional marijuana users test positive for a week or more after a single smoke.
Tests that treat recreational use as being the same as use on the job are a problem. While marijuana affects a user's ability to work or drive safely at the time, occasional use has no lingering effects beyond a good night's sleep. While the metabolites remain in the system for long periods, the drug's narcotic effect is gone within a few hours. Testing for after-hours use is essentially little more than a test of character - something that can be better accomplished without chemistry.
Concerned by all this, I rang the person whose opinion on such matters I trust the most; Ross Bell from the Drug Foundation. He said employers had fallen for what he called the "hoax" that drug tests make work places safe.
Others too have fallen for the hoax.
Early this year the Prime Minister justified his Government's record immigration numbers by saying that young New Zealanders were under-employed because they were routinely failing drug tests. His comments were found to be statistically dodgy: Ministry of Social Development figures show only half a per cent of beneficiaries failed pre-employment drug tests. While data for non-beneficiaries is harder to come by, the Drug Detection Agency says around 5 per cent of the random and pre-employment tests it conducts are failures.
At this point we may conclude there is no problem at all. On the contrary, this is where the problem begins. Bill English was quite right to recognise an issue, but was skew-whiff on the solution. The small numbers of people affected are most often the people we want as a country to get into work.
Employment is not a fix all for the social problems that exist within troubled communities but it sure-as-hell is an important component. By knocking people out because they smoke dope we are entrenched in issues particularly around key areas of Maori and youth unemployment - and, of course, all of the problems that churn around that.
Reaching in to another labour pool may tick a box for employers, but the broader problem of getting Kiwis, particularly young Kiwis, into work where they can become active members of our society remains.
Looking at a burgeoning prison population and saying that the Department of Corrections will solve the issues is as unrealistic as it is expensive. We need to tackle problems before they arise, and employment is a key to that. Testing for intoxication at work is important, but we aren't doing that, we are simply creating hurdles on a path to broader social goals.
Small things in young people's lives have very big ripple effects. The troubled young lad I met remains as he has always been, on the fringes of society. Where he goes from here is unknown, but without question he - all of us - would have been all the better for having a job.
What's my advice to him? Drink more and give up dope. Yeah, because alcohol causes no harms, right?