In 1988, 13.6% of all workplace drug tests were positive. 1988 is when the Federal Drug-free Workplace Act went into effect, followed by the Omnibus Transportation Employee Testing Act of 1991 three years later. Deterrence makes a difference.

Quest Diagnostics’ 2013 Drug Testing Index has tracked drug testing statistics for 20 years now. The study separates statistics from federally mandated industries (e.g. commercial truck drivers) from those from the general workforce. It’s a simple matter to see that the mandated industries have much lower positive rates.

Behavior modification

As a result of many years of testing, these folks have dramatically changed their behavior. In the first 6 months of 2012, federally mandated employees tested positive only 1.7% of the time. That’s pretty good. In contrast, during the same time frame, the general workforce rate was 240% higher at 4.1%. That’s a lot better than 13.6%, but keep in mind these numbers are for businesses that test. Many businesses still don’t—and that makes them the employers of choice for those that use and abuse.

Many substance abusers who know they’re subject to testing will modify their behaviors in order to keep their jobs. SAMHSA’s most recent study says 8.9% of all full-time employees are illicit drug users.

It stands to reason, then, that most of them are working in businesses that don’t test.

Testing isn’t a “gotcha” thing.

It’s about keeping the work environment safe. Deterrence. Behavior modification. It works.