Guest Blog Series: The Random Selection Process

Guest Blog Series: The Random Selection Process

“Well, how exactly does the random process work?” This is one of the most common questions heard in the Program Administration Department at Tomo. Before we delve into the details behind how the random procedure works, let’s first define what a random process is and what it’s used for. A random selection process is when an employee or multiple employees are chosen anonymously for drug testing by a computer-generated algorithm. Department of Transportation companies are required to implement a random drug testing program for employees who are in safety-sensitive positions. Drug and alcohol free workplaces use random drug testing programs to deter employee drug use, give employees a reason to say no to drugs, and identify employees with drug problems who could benefit from intervention and treatment.

What program does Tomo use for random selection?
At Tomo, we use a program called DrugPak to generate clients’ random selections. The DrugPak software is approved by the Department of Transportation (DOT) and also meets the many other needs of our clients. The process is completed using a proven and well-established random number generator. It is based on the “linear congruential algorithm” invented by D.H. Lehm.

What does DrugPak require to randomly select employees for testing?
Prior to each random selection, clients will be asked to update their employee list. The updated employee list is then imported into DrugPak, giving us the eligible testing pool(s). Updating the list is critical each time a random selection process occurs to ensure the eligible testing pool is accurate and truly random.

How often should you randomly test?
When a client joins Tomo, their account manager will help them decide how often they want to test their employees and the number of employees they wish to test each time. The number can be a specific number of people per random selection or a percentage of the eligible testing pool. DOT testing pools must be tested at a minimum of the currently established percentage set forth by the Department of Transportation for each DOT administration. DrugPak can accommodate any size of testing pool and has no set limit on how many participants can be in a testing pool.

How does DrugPak randomly choose employees?
After the updated employee list has been imported into the DrugPak software, a random number will be assigned to each person in the eligible testing pool. These numbers are not sequential and change every time a random selection is generated. DrugPak then sorts the random numbers chronologically, and the lowest numbers are the random selections; all remaining numbers then become the alternates list.

For Example:
Tomo client has 50 employees; they want to test 10 employees each time. Each of the 50 employees will be assigned a random number by DrugPak; the 10 employees with the lowest random numbers will be designated as the selected participants. The remaining 45 employees will be designated as alternates, to be used in the event that a selected donor is not available.

Why are the same employees chosen multiple times?
It is NOT uncommon for the same employee to be selected numerous times in a row! DrugPak distributes selections independent of any criteria other than the fact that the participant is in the eligible testing pool. For this reason, it is quite normal and natural for a participant to be selected more than once. Each selection is utterly independent of the prior selections. This means the same employee(s) can get selected multiple times in a row or the same employees could not be selected multiple times in a row. DrugPak’s random selection process is completely free of bias.

Why implement a random drug testing program?
Drug-free workplace random testing helps employers ensure that they have a safer working environment for their employees by potentially identifying an employee that is unable to safely perform their job duties. Also, many employees will refrain from using prohibited substances when they know their employer has and enforces a drug-free workplace policy. Department of Transportation regulations required each administration employee pool to be tested for drugs and alcohol at specific percentages annually.


If you would like to know more information about the DrugPak random selection process or have additional questions about the software, please contact us! If you’re interested in developing a program for random student drug testing, contact Tomo Drug Testing. Based in Springfield, St. Louis, and Kansas City, Missouri, and Evansville and Indianapolis, Indiana, we offer customized solutions to make drug testing simple, and our nationwide network of clinics and providers allows Tomo Drug Testing to be available anytime, anywhere. For a free needs analysis, give us a call today at 1-888-379-7697 or contact us online. We would be happy to help.


The Random Selection Process blog was written by Beth Ruckman. Beth has worked at Tomo Drug Testing for four and a half years and is a Client Database Coordinator. Her primary function is to generate the random testing lists. She also plays a significant role in ensuring compliance for Tomo clients with DOT-regulated employees and drug-free workplace environments.