Definitions of common terms


The agreement of a young person to participate in research in cases where legal consent is provided by a parent or guardian.

Blinding, single- or double-blind studies

Studies in which the participants (single blind) or the participants and researchers (double blind) do not know which treatment is being used.

Clinical trial

Any research study that prospectively assigns human participants or groups of humans to one or more health-related interventions to evaluate the effects on health outcomes. Interventions include but are not restricted to experimental drugs, cells and other biological products, vaccines, medical devices, surgical and other medical treatments and procedures, psychotherapeutic and other behavioural therapies, process-of-care changes, preventive care strategies and educational interventions.  They may also be used to evaluate diagnostic or screening tests and new ways to detect disease. Clinical trials test new treatments or interventions as a means to prevent, detect, treat or manage various diseases or medical conditions.  They study how people respond to a new treatment or intervention and what side effects might occur in order to determine if a new treatment or intervention works, if it is safe, and if it is better than the treatments or interventions that are already available. Clinical trials might also compare existing treatments or interventions, test new ways to use or combine existing treatments or interventions or observe how people respond to factors that might affect their health.

Diagnostic or screening trials

Studies that test the best way to detect certain diseases or conditions.

Good clinical practice (GCP)

International standards of conduct for clinical trials. Two standards have been approved for use in Australia: one developed by the International Conference on Harmonisation (ICH) and one developed by the International Organization for Standardization (ISO), the ISO 14155. GCP standards are mandatory for all Australian clinical drug and device trials.

Healthy participant

A person with no known significant health problems who takes part in clinical research to test a new treatment.

Inclusion/exclusion criteria

Factors that allow someone to be part of a clinical trial (inclusion criteria) or that exclude participation (exclusion criteria).

Informed consent

  1. when research participants are  fully informed about the requirements, risks and potential benefits of research before deciding to take part in it.
  2. the process for ensuring that participants are properly informed and have validly provided their consent.

Medical devices

Are artificial devices used in or on the patient’s body for treatment of a disease or condition, such as a stent to keep someone’s arteries open and help their heart function better, an implant used in a knee replacement,  a pacemaker, or contact lenses.

Participant Information and Consent Form

Provides information about a clinical trial to prospective participants and a mechanism for obtaining their written consent to participate. The information should include details such as the trial’s purpose, duration, required procedures, risks and potential benefits.

Patient participant

A person with a known health problem who takes part in research to better understand, diagnose, treat, or cure that disease or condition.


A treatment that appears to be the same as the new treatment but does not have any active ingredients.

Prevention trials

Studies that test ways to prevent a disease or condition in people who have never had the disease or to prevent the disease from returning.


A detailed clinical trial plan that includes the purpose and procedures of the research and who can be part of the trial.

Principal investigator

The researcher who leads the research team.


The process by which participants are randomly assigned (usually by a computer program) to different treatment groups in a clinical trial.

Side effects

Any associated effects of, or reactions to, the experimental treatment (e.g. nausea, tiredness, dizziness).

Phases of clinical trials

Different phases of clinical trials, from safety studies in small groups to large safety and efficacy studies and population studies. Clinical trial stages are commonly referred to as ‘phases’ – e.g. Phase I, II, III or IV.

Treatment trials

Studies that test new treatments, including new medicines, new combinations of medicines, new approaches to surgery or other interventions.