Research terms explained

A group of patients receiving a particular treatment in a clinical trial. The patients are spilt into groups or ‘arms’ of a study depending on what treatment they are allocated. There could be two, three or more arms.

This term applies to trials where a new treatment is compared against another treatment or a placebo. A trial is ‘single-blind’ if either the participants or the researchers do not know which option the participants are receiving, and ‘double-blind’ if both the participants and the researchers do not know which option the participants are receiving. This makes the results of the trial more objective and therefore more reliable.

Standard record form containing data and other information about each participant in a trial.

A medical researcher in charge of carrying out a clinical trial's protocol.

A clinical trial is a research study to answer specific questions about vaccines or new therapies or new ways of using known treatments. Clinical trials (also called medical research and research studies) are used to determine whether new drugs or treatments are both safe and effective.

A group of individuals with some characteristics in common, for example, a group of people born within the same period would be referred to as a birth cohort.

A specific circumstance when the use of a treatment could be harmful, for example, aspirin allergy is a contraindication to taking aspirin.

An alternative to a new treatment that is used as a comparison. Controls are usually either an existing treatment, a placebo or no treatment (observation only).

An independent committee composed of community representatives and clinical research experts that review data while a clinical trial is in progress to make sure that it is being carried out safely.

A description of requirements for people that can (inclusion criteria) or cannot (exclusion criteria) take part in a trial (e.g. must be 18 years of age or older).

Contact by the research team with a study participant after they have completed a study intervention to assess current status of their condition.

The standard for the design, implementation, conduct, and reporting of clinical trials to provide assurance to regulatory agencies and the general public that the data is credible and that the rights of subjects are protected.

The process of learning what is involved in a clinical trial to decide whether or not to take part.

A trial being carried out at more than one location which could be local, national or international.

A study where the researcher is not directly controlling the experiment but instead observing behaviour or outcomes. No attempt is made to change the outcome, for example no treatment is given.

A clinical trial in which doctors and participants know which drug or vaccine is being administered.

A review of a trial protocol by a group of independent experts.

A 'dummy' treatment that resembles a medical treatment but is intended to have no physical effect on a participant. A new treatment is often compared against a placebo to get more reliable evidence about its effectiveness. Patients who receive a placebo should still also receive the best standard of care.

A study plan on which all clinical trials are based. The plan is carefully designed to protect the health of the participants as well as answer specific research questions. A protocol describes what types of people may participate in the trial, the types of tests, procedures, medications, and dosages and the length of the study.

A method of research that involves listening to what people say about a condition, service or treatment and establishing what is important to them. This can take place by means of interviews and focus groups.

A method of research concerned with the measurement of scientific and medical outcomes where research data is presented in a numerical way.

In a randomised controlled trial, participants are allocated to receive one type of treatment or another by a random process, usually using a computer. This helps to ensure the results are objective and unbiased.

Research in which a group of participants is identified and then studied from that point backward in time, usually via their medical records.