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.

  • Objective measure

    A measurement that follows a standardised procedure which is less open to subjective interpretation by potentially biased observers and people in the study.

  • Observational study

    A retrospective or prospective study in which the investigator observes the natural course of events with or without control groups (for example, cohort studies and case–control studies).

  • Odds ratio

    Compares the odds (probability) of something happening in 1 group with the odds of it happening in another. An odds ratio of 1 shows that the odds of the event happening (for example, a person developing a disease or a treatment working) is the same for both groups. An odds ratio of greater than 1 means that the event is more likely in the first group than the second. An odds ratio of less than 1 means that the event is less likely in the first group than in the second group.

  • Office for Market Access

    The first point of contact for talking to NICE about future products, providing help for all sectors of the life sciences industry: pharmaceutical; health technology; diagnostics; and devices; and for anyone with a question.

  • Off-label prescribing

    A medicine with an existing UK marketing authorisation that is used outside the terms of its marketing authorisation, for example, by indication, dose, route or patient population.

  • OPCS Classification of Interventions and Procedures

    A classification system (originally developed by the Office of Population Censuses and Surveys) to enable data relating to procedures to be collected. Procedures covered by interventional procedures guidance are listed according to version 4.6 of the classification.
  • Opportunity costs

    The opportunity cost of investing in an intervention is the value of the benefits generated by other healthcare programmes that are displaced by its introduction. This may be best measured by the health benefits that could have been achieved had the money been spent on the next best alternative healthcare intervention.

  • Organisations for patients, people using services and carers

    Organisations of patients, people using services, carers, communities and other lay members, including those that represent people from groups protected by equalities legislation.

  • Outcomes

    The impact that a test, treatment, policy, programme or other intervention has on a person, group or population. Depending on the intervention, outcomes could include changes in knowledge and behaviour related to health or in people's health and wellbeing, the number of patients who fully recover from an illness or the number of hospital admissions, and an improvement or deterioration in someone's health, symptoms or situation.
  • Overview

    At NICE, this is a document that summarises the findings from the evidence gathered for a guidance that is being developed. It is used to support the relevant committee in making draft recommendations.