This week brought furore over the thirteen thousand (or so) youths neither in education, employment or training.

Employers complained of difficulty finding suitable candidates who can pass a drug test. The Prime Minister echoed their concerns. Migrant workers, according to reports, were more likely to show up on time and pass a drug test.

The opposition asked what the government is doing about youth drug problems, if those problems are indeed so prevalent, and why so few beneficiaries subject to drug testing wind up failing those tests. And a few people sensibly pointed to the inadequacy of marijuana tests in detecting current usage - the tests can pick up use that happened weeks prior to the test.

For all of the furore, nobody has stopped to ask why there is so much drug testing.

I have a hypothesis.

Company directors are liable for substantial penalties if they cannot demonstrate that they have taken all practicable measures to ensure workplace health and safety. If on-the-job impairment is a potential health and safety risk, a company director has to show how she has mitigated that risk.

A drunk worker is pretty easy to identify. A cannabis-impaired worker would be harder to point out – or at least not reliably. If an impaired worker had an accident, and the firm could not point to having a regime in place, the directors could be in substantial personal trouble.

What is the easiest solution? Overkill. Put in a drug testing regime, easily available from health and safety consultants. The directors can then tick the box showing that a risk mitigation regime is in place. The auditors will be happy. If something bad does happen, the company can point to the testing regime to show it had taken all practicable steps to mitigate the risk.

And it simply does not matter that much to the regulators that the tests would pick up all kinds of use that imposes no risk at all.

As Bryce Wilkinson’s report on scaffolding costs last year demonstrated, New Zealand’s health and safety regime encourages a cost-heavy, risk-averse approach that has little regard for cost-effectiveness, or for sanity.

If only there were testing to check whether Parliament and Worksafe were stoned when passing regulations. Perhaps we should collect urine samples before important votes, just in case.