The NICE glossary provides brief definitions and explanations of terms used on the website. The terms describe how NICE works and how its guidance is produced.

Our glossary excludes specific clinical and medical terms. If you cannot find the term you are looking for, please email us so that we can consider adding it to the glossary.

Some definitions and examples are based on those in the HTAi consumer and patient glossary, with thanks to Health Technology Assessment International.

For terms used in social care, the Care and Support Jargon Buster from Think Local Act Personal is a useful guide to the most commonly used social care words and phrases, and what they mean.

  • Lay member

    A NICE committee member whose background could be as a person using health or care services, a carer, an advocate, a member or officer of a voluntary or community organisation, or a member of the general public. The lay member's role is the same as other committee members, and also includes contributing a lay perspective, and highlighting patient and carer issues.

  • Licensed medicine

    A drug that has been assessed for efficacy, safety and quality, has been manufactured to appropriate quality standards, and, when placed on the market, is accompanied by appropriate product information and labelling, that is, it has been authorised for marketing.

  • Life years gained

    Average years of life gained per person as a result of an intervention.

  • Likelihood ratio

    The ratio of the probability that a person with a condition has a specified test result to the probability that a person without the condition has the same specified test result.
  • Longitudinal study

    A study of the same group of people at different times. This contrasts with a cross-sectional study, which observes a group of people at a point in time.