In a study of high tech industries, researchers found that "drug testing programs do not succeed in improving productivity. Surprisingly, companies adopting drug testing programs are found to exhibit lower levels of productivity than their counterparts that do not. The regression coefficients representing potential effects of drug testing programs on productivity are both negative and significant. Both pre-employment and random testing of workers are found to be associated with lower levels of productivity."

Source

Shepard, Edward M., and Thomas J. Clifton, Drug Testing and Labor Productivity: Estimates Applying a Production Function Model, Institute of Industrial Relations, Research Paper No. 18, Le Moyne University, Syracuse, NY (1998), p. 1.
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