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Commonly used terms in clinical research


Assent Form: A written document that describes all aspects of the research study that would be relevant to a child’s decision to participate in a research study, written in language that is appropriate for the intended age of the children being asked to participate.


Clinical Research Trial/Study: Research study that uses human participants to increase our knowledge in a carefully planned and controlled way. Clinical trials use humans as participants either directly (survey questions, blood tests, physical examinations, etc.) or indirectly (a review of medical records). The term clinical trial and clinical study are interchangeable.


Informed Consent: Voluntary agreement by a parent or guardian for their child to participate in a research study after having been informed of all aspects of the research study.


Informed Consent form: A written document that describes all aspects of the research study that are relevant to their decision to participate. This includes the reason for the study, how many people will participate, what is involved (tests, treatment, questionnaires, etc.) and the timing, the risks and benefits of participating, the alternatives to participating, the confidentiality, privacy and rights of the participants, whom to contact for questions, as well as a section for participant signature.


Control Group: A group of participants in a research study who do not receive the experimental intervention being studied. Results are determined by comparing the control group to a group who received the experimental intervention.


Efficacy: How well a treatment or intervention works in a clinical research study.


Eligibility: The determination of who can participate in a particular research study based on criteria specific to each study. Criteria include factors such as age, gender, medical history, diagnosis, etc.


Intervention: The entity or thing (drug, vaccine, psychological care, diet, device, etc) that is being researched.


Investigator: The person responsible for the conduct of the clinical research study.  If the study is being run by a team of individuals, then the team leader is referred to as the Principal Investigator.


Participant: Individual who participates in the research study.


Phase (of a Clinical Trial): Clinical trials involving new medications are commonly classified into four phases:

  • Phase I studies determines whether the medication is safe in humans. These studies can involve healthy volunteers, as well as ailing participants. The number of participants is usually very small. They typically determine the dose or range of doses to use in the phase II study.
  • Phase II studies determine whether the medication may have any biological activity or efficacy in order to determine if the medication should continue to be researched. Safety will also continue to be monitored.
  • Phase III studies determine the drug’s efficacy in a large number of participants. These studies are typically randomized.
  • Phase IV studies determine and monitor any of the medication’s long term effects.


Placebo: An inactive pill, substance, or other intervention that does not affect the disease or condition being studied. Some research studies involve a group of participants who receive the experimental intervention and a group who receive a placebo intervention. Results are determined by comparing the data from the two groups. Placebos help investigators determine if the experimental intervention is the cause of responses exhibited by the participants.


Protocol: A written detailed document that describes in detail the research study. It includes the scientific basis for the study, the question being asked in the study, a description of who is allowed to take part, information about study treatments, the procedures associated with the study, the possible benefits or risks, and other important information.


Randomization: Some research studies randomize participants. This means that the participants are put into a treatment/intervention group by chance, like flipping a coin or pulling a number out of a hat. This is used in order to make sure study results are fair.


Research: This is the gathering of data, information and facts for the advancement of knowledge.


Research Ethics Board (REB): A committee dedicated to ensuring the rights, safety and well-being of the participants of a clinical research study. For more information, see (link to REB page).


Side Effect: Any action or effect of an intervention that is not the intended effect or action of the intervention. For example, many people take medications to help with allergies, with the intention of decreasing their stuffy nose, and itchy eyes. However, a common side effect of allergy medications is drowsiness, as this is not the intended action/effect of the medication. Typically side effects are negative effects such as headaches or nausea, but could also be positive.


Study Sponsor: Study sponsor means an individual, company, institution or organization which takes responsibility for the initiation, management and/or financing of a clinical trial.

Le contenu de ces pages est en anglais mais pourra être fourni en français sur demande. 


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