Consent forms and trial listings are written in a dialect all their own. Every term below is defined in one or two plain sentences, so you can read a Participant Information and Consent Form without a second tab open. Each definition stands on its own.
A to D
Adverse event (AE): any unfavourable medical occurrence during a trial, whether or not it's caused by the study treatment. All of them are recorded and assessed.
ANZCTR: the Australian New Zealand Clinical Trials Registry, a public register of trials. Every legitimate Australian trial should appear on ANZCTR or ClinicalTrials.gov.
Baseline: the measurements taken just before you start the study treatment, used as the starting point everything after is compared against.
Blinding: keeping participants (single-blind) or participants and study doctors (double-blind) from knowing who is in which treatment group, so expectations can't distort the results. How it works in practice is covered in will I get a placebo?
Comparator: the treatment the investigational one is measured against. It can be an existing approved treatment or a placebo.
CRO (contract research organisation): a company a sponsor hires to run parts of a trial, such as monitoring sites and managing data.
Data safety monitoring board (DSMB): an independent group of experts that reviews a trial's accumulating safety data while it runs, with the power to recommend pausing or stopping the study.
E to L
Eligibility criteria: the rules deciding who can join a specific trial, split into inclusion criteria (what you must have) and exclusion criteria (what you must not have). They're fixed in the protocol and approved by an ethics committee. Not meeting them is what being screened out means.
Enrolment: the point at which you formally join a trial, after consent and successful screening.
First-in-human: the first study in which a treatment is given to people, usually a small, intensively monitored Phase 1 study.
GCP (good clinical practice): the international standard for how trials must be designed, run and reported, with participant rights, safety and wellbeing placed above the interests of science.
HREC (human research ethics committee): the independent committee that reviews and approves a trial before it opens and oversees it while it runs. Its name and reference must appear on your consent form.
Informed consent: the process of understanding a trial, including its risks, before voluntarily agreeing to take part. It's ongoing, not a one-off signature, and it's one of your rights as a participant.
Investigational treatment (or investigational product): the treatment being tested, not yet registered for the use being studied.
M to R
Monitor: a person from the sponsor or CRO who checks that a site is following the protocol and recording data accurately.
Open-label: a study, or a phase of one, in which everyone knows which treatment is being given. An open-label extension sometimes lets participants access the active treatment after the blinded part ends.
PICF (Participant Information and Consent Form): the document that explains the study, its risks and your rights, which you sign to consent. Read the withdrawal, injury and payment clauses twice.
Placebo: an inactive version of the study treatment, identical in appearance, used so results can be compared against the effect of simply being treated and monitored.
Pre-screening: a short set of eligibility questions before any visit or consent, explained in what is pre-screening?
Principal investigator (PI): the doctor responsible for the trial at a site, including participant safety.
Protocol: the trial's rulebook: who can join, what happens at each visit, what's measured, and what stops the study. Approved before recruitment and binding on the site.
Randomisation: allocating participants to treatment groups by chance, usually by computer, so the groups are comparable and nobody chooses who gets what.
S to W
Screening / screen failure: the tests and checks after consent that confirm eligibility. A screen failure means a result fell outside the protocol's range, not that something is necessarily wrong with you.
Serious adverse event (SAE): an adverse event meeting formal seriousness criteria, such as one requiring hospitalisation. SAEs are reported to the sponsor quickly, and onward to the ethics committee and regulator where required.
Site: the hospital, clinic or research unit where a trial is run.
Sponsor: the company or institution responsible for the trial, its funding and its data. Named in your consent form.
Standard of care: the currently accepted best treatment for a condition, often the comparator in a trial.
TGA (Therapeutic Goods Administration): Australia's regulator of medicines and devices. Trials of unapproved products run under its Clinical Trial Notification or Clinical Trial Approval schemes.
Trial phase: which stage of testing a treatment has reached, from 1 to 4. Each phase asks a different question, set out in the four phases explained.
Washout period: a supervised break from a current medication before or during a study, so it doesn't interfere with the results. Never start one on your own.
Withdrawal: leaving a trial after enrolling, which you can do at any time, without giving a reason. The safe way to do it is covered in withdrawing from a clinical trial.
Met a term that isn't here? Ask the study coordinator to explain it in plain language. That's part of their job, and how they respond tells you plenty. For how all these pieces fit together in practice, start with what to expect when you join a clinical trial in Australia.
Related reading: What to expect at each stage · The four phases explained · Your rights as a participant