The NICE glossary provides brief definitions and explanations of terms and jargon used on our site. The terms describe how we work and how our guidance is produced.
Our glossary excludes specific clinical and medical terms although we intend to include these in the longer term. If you cannot find the term you are looking for, please email us so that we can consider adding it to the glossary. New terms are added regularly.
The glossary is not used for indexing the site or for navigation - for information on this, please see the NICE taxonomy.
Some definitions and examples are based on those in the ‘HTAi consumer and patient glossary’, with thanks to Health Technology Assessment International.
- Randomisation (random allocation)
Assigning participants in a research study to different groups without taking any similarities or differences between them into account. For example, it could involve using a random numbers table or a computer-generated random sequence. It means that each individual (or each group in the case of cluster randomisation) has the same chance of receiving each intervention.
- Randomised controlled trial
A study in which a number of similar people are randomly assigned to two (or more) groups to test a specific drug or treatment. One group (the experimental group) receives the treatment being tested, the other (the comparison or control group) receives an alternative treatment, a dummy treatment (placebo) or no treatment at all. The groups are followed up to see how effective the experimental treatment was. Outcomes are measured at specific times and any difference in response between the groups is assessed statistically. This method is also used to reduce bias.
See randomised controlled trial.
- Recommendation reminders
Reminders about past recommendations from NICE guidance to help NHS staff reduce the use of tests and treatments that do not work well. These are published monthly on NICE's website.
- Relative risk
The ratio of the risk of disease or death among those exposed to certain conditions compared with the risk for those who are not exposed to the same conditions (for example, the risk of people who smoke getting lung cancer compared with the risk for people who do not smoke).
If both groups face the same level of risk, the relative risk is 1. If the first group had a relative risk of 2, subjects in that group would be twice as likely to have the event happen. A relative risk of less than one means the outcome is less likely in the first group. Relative risk is sometimes referred to as risk ratio.
The ability to get the same or similar result each time a study is repeated with a different population or group.
- Remuneration and Terms of Service Committee
A subcommittee of NICE's board that sets the salaries and terms of service for senior staff.
- Research question
A question used to search for evidence as part of the development of NICE guidance. See also clinical question.
Before interventional procedures guidance is issued to the NHS, consultees can ask for a 'resolution' if they think that the guidance is inaccurate or the process for developing interventional procedures guidance hasn't been followed. During the resolution process, any concerns raised by the consultees are investigated.
- Retrospective study
A research study that focuses on the past and present. The study examines past exposure to suspected risk factors for the disease or condition. Unlike prospective studies, it does not cover events that occur after the study group is selected.
- Review date
The review date listed in the guidance is the date at which we plan to begin the review process. From this date, we collect evidence to inform our review proposal. We also seek the views of stakeholders to identify any change in practice or additional relevant published evidence. If a large amount of new or significant evidence has been produced since the original guidance, we may propose a review of the guidance. However, if limited new evidence has been produced, we may propose to delay the review.
- Risk factor
Any aspect of a person's lifestyle, environment or pre-existing health condition that may increase their risk of developing a specific disease or condition.
- Risk Management Committee
A subcommittee of NICE's board that advises staff on identifying risks to the organisation and how to reduce them. Its work includes making sure NICE follows legislation on issues such as health and safety and data protection, and advising on preventing errors in published guidance.
- Risk ratio
See relative risk.
This page was last updated: 15 April 2011