Actually, drug testing is a good measure of impulsivity and distractibility. If a person cannot manage to pass a drug test, they lack self control and are likely to do things like bitch out customers and break expensive equipment.
The self control aspect of drug tests are probably a pretty good proxy for IQ—ADHD is correlated with a substantial 10 point drop in IQ.
You could just as well test for salt consumption as cocaine. The point is to check whether the applicant can hold their shit together for a few days for something as important as a job.
Yeah, that's how I take it. I don't ingest any substances that would cause any problems on a drug test, but it's a huge red flag for me that the company most likely 1) is run by bureaucrats; and 2) wants to control my private life. More viscerally, I just find the whole "report to a facility and urinate on command" thing unpleasant and weird and will prefer companies that don't subject me to such indignities. And some companies demand it several times per year!
The point is that it's very easy for a company to measure the metrics they should care about (i.e. quality and quantity of work output) rather than making random correlations.
An IQ test is also a good proxy for an IQ test: but there would probably be an outcry if companies started basing performance reviews directly on an IQ test.
The self control aspect of drug tests are probably a pretty good proxy for IQ—ADHD is correlated with a substantial 10 point drop in IQ.
You could just as well test for salt consumption as cocaine. The point is to check whether the applicant can hold their shit together for a few days for something as important as a job.