The percentage of medium-to large-sized companies that have instituted drug testing programs has almost doubled from 1988 to 1993 -- from nearly 32 percent to over 62 percent. However, the effectiveness of drug testing programs has been questioned.

The military has an especially aggressive approach that combines mandatory random drug testing and zero tolerance -- no "second chances" -- a type of program relatively rare in the private sector. How effective is the military's approach?

According to a working paper published by the National Bureau of Economic Research:

• Drug use by military personal and civilian workers mirrored one another before the military instituted drug-testing in 1981; but now, according to the study's authors, drug abuse among military workers is far less prevalent than among their civilian counterparts.

• Military personnel are about 16 percent less likely to report using drugs in the past year on surveys than their civilian counterparts.

• And drug use rates in the military fell from 27.6 percent in 1980 to only 3.4 percent in 1992.

After taking into account selection bias -- potential drug-using recruits are aware of the drug-testing program and steer clear of a military career -- the deterrence effect of the military's program ranges between 4 percent and 16 percent, the authors calculate.

Nevertheless, drug use hasn't been eradicated from the military, and the researchers note that the military's more lenient approach in the early 1980s still showed a sizable deterrence effect.

Source: Christopher Farrell, "Employee Drug Testing is Effective," NBER Digest, March 2000; Stephen Mehay and Rosalie Liccardo Pacula, "The Effectiveness of Workplace Drug Prevention Policies: Does 'Zero Tolerance' Work?" NBER Working Paper No. 7383, October 1999, National Bureau Of Economic Research, 1050 Massachusetts Avenue, Cambridge, Mass. 02138, (617) 868-3900.

For NBER summary http://www.nber.org/digest/mar00/w7383.html

For more on Drug Use and Control http://www.ncpa.org/pd/social/social4.html