Random refers to the method by which employees are selected to be tested. Because random tests are unannounced employees cannot predict when or if they will be selected for a drug test. For this reason, random testing is credited with having a high deterrent effect, making it very popular for workplace drug testing. Random testing can be applied to an entire employee population (universal) or limited to certain locations or groups of employees (such as workers in safety-sensitive occupations).
The selection is typically computer generated and based on an annual frequency rate of a percentage of the pool of employees subject to random testing. For example, an employer may wish to test at a 50 percent “random frequency rate.” This means that if there are 100 employees, the company will conduct 50 random selections during the year. It does not mean that 50 different employees will be tested. Usually, all employees subject to random testing are eligible to be selected each time names are randomly selected by the computer. No one knows when their name will be selected only that it could be… hence, the deterrent effect.
