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Ethical Treatment of Human Factors Test Participants

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As a university student, I worked in a psychobiology lab where we studied the physiology of emotions. Our lab housed rats, mice, and chickens. Because I was a lowly undergraduate, I was saddled with some of the less glamorous chores in the lab such as cleaning out the rat cages, refreshing the bedding, and making sure the rats had enough rat chow and water. For the record, yes, it really is called rat chow.

A lab rat in a cage with food pellets
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In return, the department gave me permission to conduct my own independent research as well. From time to time, we would conduct research on people (usually college sophomores enrolled in Psychology classes). One thing always struck me though: we called both the rats and the college sophomores “research subjects.” This was a nod to experimental rigor and control, but it felt a bit dehumanizing to the lowly college sophomore. I did not mind calling the rats subjects; they did not seem to mind. But humans, even college sophomores, seemed deserving of more respect.

Thankfully, things changed over time, and it is now standard to refer to human subjects as research participants. This reflects their humanity, shows some respect, and reminds us that they participate voluntarily and have the right to leave anytime, and for any reason. Indeed, these research participants are doing us a favor. Without them, we have no research.

A picture of a mouse with the label 'this is a subject' next to a picture of a college student with the label 'this is a participant'

Usability Testing, Not User Testing

From time to time, as a human factors engineer, I get that same old feeling (my skin crawls) when I hear colleagues refer to usability testing as user testing. Please understand that we are not testing the user at all. Instead, we are testing the usability of a product or prototype. The research participant (user) is simply kind enough to assist us in this endeavor. Calling this activity user testing reinforces the notion that there are good participants and bad participants, and that the good ones can complete the tasks correctly, whereas the bad ones – not so much. Put yourself in the shoes of the user. Do you want to sign up for user testing?

The Usability Test Participant’s View

Participating in research can be uncomfortable. Imagine you have signed up to be a research participant for a new medical device. You agree to a particular time and date and arrive at the usability lab on time. There, you complete and sign a confidentiality form and patiently wait for your name to be called. So far, so good. Eventually, a moderator emerges to greet you and appears genuinely happy to meet you. Then you follow your moderator into the research lab.

Here’s where it gets rough. You look around, observing the one-way mirror, the cameras on the ceiling, and the microphones. You see a clipboard, some papers, and some unfamiliar equipment. Imagine what is going through your mind at that point. Who is behind that one-way mirror? Does anyone back there know me? How would I know? Are they recording me right now? How do I look on the video? I hate the sound of my own voice on recordings. Is this going to be difficult? What if I screw up? Am I even qualified to be here?

Protecting the Human Factors Research Participant

As a researcher, at this point, it is your responsibility to protect the participant from harm, which could take on various forms For example, the participant could be harmed physically if they accidentally get stuck by a needle. They could be harmed emotionally if they are made to feel foolish and anxious. Finally their reputation could be harmed if their performance data or personal information is shared with people they know or will come to know.

Human Factors Engineers typically adhere to the American Psychological Association (APA) guidelines. These state that researchers respect the people who participate and show concern for their dignity and welfare. For human factors research and usability testing it is really important to become familiar with these guidelines, so here is our summary and explanation of each guideline:

1. Do no harm

As in the practice of medicine, the appropriate approach is to first do no harm. The risk of doing harm is considered reasonable if there are no risks greater than those based in their actual day-to-day environment and activities.

2. Accurately describe risks to potential participants

Participants have a right to understand potential risks involved in participating in your study. It is never appropriate to put someone at risk without their knowledge. 

3. Ensure that participation is voluntary

No participant should ever be coerced into participating. Researchers must obtain informed consent from all participants. The informed consent should describe in plain language the goals of the project, the potential risks and benefits, the procedures for maintaining confidentiality, and the incentives or payments offered. It should state that the participant understands the nature and risks of the study, that their participation is voluntary, and that they know they may withdraw at any time. Once this information has been communicated, participants can agree to participate in the study by signing the informed consent.

4. Minimize discomfort to participants

Human factors research, especially in healthcare, can cover some pretty touchy topics. In recent years, our company has worked on projects involving gender transition surgery, pregnancy testing, incontinence, sexual difficulties, diet and eating habits, mental health, and sexually transmitted diseases. These can be uncomfortable to discuss, so every effort should be made to put the participant at ease and show them respect.

5. Maintain confidentiality

Confidentiality refers to the participants’ rights to not have their data revealed to others without their permission. Participants should be told that all results will be kept anonymous and confidential. Confidentiality is usually maintained by substituting codes for names and storing data in locked cabinets. Explain to participants why you need any personal information, what it will be used for, how long you will keep it, and how it will be destroyed. 

6. Do not unnecessarily invade privacy

Privacy refers to the participants’ control over how their information is shared. If you collect personal information from the participant then you are obligated to protect that information and only use it when it is absolutely necessary.

7. Use deception only when absolutely necessary

Usability studies rarely need to deceive participants, except in the event of disguising the brand name or sponsoring organization. 

8. Provide a debriefing to all participants

The idea of debriefing comes from military practice. At the end of military missions, personnel discuss what went well and what went poorly. This debriefing enables participants to process problems or emotional issues involved in the mission. In usability research, debriefing serves a similar purpose. Once the study is over, researchers discuss the purpose of the session with the participant and field any questions the participant might have.

9. Treat participants with dignity and respect

We must always treat research participants with respect. They are often self-conscious because they feel that the performance is being evaluated and that they are not performing well. The researcher needs to put the participants at ease, assuring them that the product is being evaluated, not the participant.

10. Allow participants to withdraw at any time for any reason

Participants should never feel trapped, physically or by social obligation. That would be an awful feeling, and you just never want to do that to anyone.

Human Factors Engineering and Institutional Review Boards (IRB)

Often researchers use an institutional review board (IRB) to review the materials, procedure, and confidentiality measures provided by the study. IRBs review and certify the adequacy of consent forms and the potential risk for the participant and whether it is outweighed by the overall benefits of the research. Many governmental and university research organizations have their own IRBs, but there are also very good third-party IRBs, who are timely and reasonably priced.

These simple guidelines can be used as a checklist to make sure you are doing what is necessary to protect and show respect for your research participants.

Contact us if you need assistance with usability testing or other user experience research.


Rubin, J. & Chisnel, D. (2008) – Handbook of Usability Testing: How to Plan Design, and Conduct Effective Tests. Indianapolis, IN: Wiley

American Psychological Association – Ethical Principles Underlying Human Research Participant Protections. Retrieved on 7/13/22 from

Russell Branaghan photo

Russell Branaghan President

Dr. Russell J. Branaghan is Professor Emeritus of Human Systems Engineering and User Experience at Arizona State University. Russ also serves as Visiting Professor of Human Factors in the Master of Product Design and Development Program at Northwestern. Before joining ASU, Russ spent 15 years in industry leading human factors research teams at Hewlett-Packard, IBM and Fitch. Currently, Russ serves as Founder/President at Research Collective, a Human Factors research consultancy. You can find Russ on LinkedIn here.