Subjects, Patients, Participants, Volunteers, Cases…

All these terms essentially describe the same thing, so why is it appropriate to use subject in some cases but not others? And why can’t we just default to participants?

With all these options, how does a new researcher figure out what terminology to use in study advertising, ethics applications, and manuscripts?

In this post I’ll go over the following terms one at a time, and explain when it is appropriate to use each of these terms, so that you’ll be apply this confidently to your own studies.

Before I get started, bear in mind that whatever you choose, you’ll need to be consistent; never attempt to use these terms interchangeably to describe the same subjects as it may read as if there are multiple different groups (e.g., one group of participants and other groups of subjects).


A participant is a person that voluntarily participates in a study. This is perhaps the most accepted terms and is generally recommended when in doubt (provided the subject of investigation is human).

At WhiteCloud, we use Participants to refer to all of our human volunteers. This is also the case for other recruitment websites like and

[learn how to combine Callforparticipants with WhiteCloud for an ultimate recruitment strategy]

A participant is a person that willingly and actively participates in the study. For example, they will communicate with the researcher, provide informed consent, may attend a clinic or lab for data collection, or take part by survey or phone. Importantly, the person as a whole is studied. For example, perceptions, beliefs, opinions, experiences, or some aspect of mental or physical ability.


The term subject describes the person or thing that is the topic of study. provides a definition of subject as:

that which forms a basic matter of thought, discussion, investigation,etc.

Subsequently, subject can be used to describe non-humans, such as animals, plants, minerals, or machines.

This compatibility with non-humans is the reason why many researchers protest the use of the term in human research, as it implies that the person had limited autonomy, or was not actively involved in the study. Although some disciplines continue to use and accept this term, there is a growing awareness for ethical and respectful consideration, and subject should be used judiciously when working with humans.

This is not to say that all instances of subject can, or should, be immediately replaced with participant.

As mentioned earlier, subject is perfectly acceptable to describe a non-human subject.

It is also appropriate to use subject to describe a human when the subject of investigation is not actively participating in the study. For example, an infant or child. Another example is in cases of retrospective analyses, where the data was collected under non-research conditions, but is being analysed for research purposes. In these cases, the person being studied is either unaware of their involvement, or was aware that their data may be used for research purposes, so to refer to them as a participant would be inaccurate.

Another example would be in studies of a human sample or specimen, such as in physiology studies. Although the person will have provided consent and have attended a clinic, it is not them per se, that is the subject of the investigation, but rather a sample they have provided. To discuss the findings in terms of participants implies that the whole person was studied, which is not accurate.

Try WhiteCloud to manage your next study

Spend less time on admin, and more time on research.

Learn more



A patient is a participant with a medical condition which is the interest of the investigation. Like participant, patient refers to the person as a whole.

Having already covered participant and subject, the role that patient has should be easy to identify. However, there often exists a situation where patients are compared with healthy controls. Indeed, it is appropriate to use the term controls to describe a cohort of healthy participants, however this term should not be used to describe an individual participant.

When reference is made to all participants in the study, including patients and controls, the most appropriate term would be participants. However, such combining of terminology should be avoided.


The term case comes from the family of research designs known as case studies. Without going off-topic, a case study is a design that investigates a small or single cohort of patients, either cross-sectionally, longitudinally, or in comparison with a relatively matched group of healthy control participants (i.e., the case-control design).

The word case here is used to identify the condition of interest, rather than the person. A person can have a case of a condition, however the person is not the case. Therefore, one could study a case of diabetes in a patient, or a series of cases in a cohort of patients. This is accurate because the case is in reference to the condition, not the person.


A volunteer is someone that freely offers to participate in a study. Volunteer is very similar to participant and implies that the person as a whole is actively involved in the study. It also infers that they are free from any particular factor of interest, such as a medical condition.

While not formalised, the term volunteer implies a very broad and open inclusion criteria, in that the only requirement to participate was that the participant was willing to do so. In cases where more precise criteria are required, it would be appropriate to define participants by that factor of interest, for example:

  • Athletes
  • Students
  • Parents
  • Social workers
  • Police officers

These are also appropriate alternatives to participant or volunteer that may provide more accuracy and clarity.

However, be cautious about defining individuals by disabilities or health conditions. While this remains a debated topic, the conservative approach would simply be to avoid terms like diabetic and instead use patients with diabetes.


There are many different options for terminology, and this guide should help you to identify which term is best for your study.

[maybe could put the APA link from the start here instead?]

If, after this, you’re still in doubt, the safest option may be to just use the noun that best describes the subject (e.g., infant).


Are there any other methods you use to differentiate between the terminology?

Have you ever been caught in a tricky situation because of your choice of terminology?

Keep reading

Share your thoughts


  1. Boring Cornfield April 7, 2018 at 6:51 am

    Ice cream sure sounds good right about now.

  2. Wine Lovers April 8, 2018 at 6:19 am

    Good article!

  3. Happy Lady April 9, 2018 at 2:04 am

    Don’t go sniffing that too much!

  4. Blogger Listening to Music April 14, 2018 at 2:42 am

    Do you know someone named Fred?

  5. Popcorn April 15, 2018 at 7:25 am

    Would you like some popcorn?

You must be logged in to ask a question.