The NICE Glossary provides brief definitions and explanations of terms used on our site. The terms describe how we work and how our 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.

  • Objective measure

    A measurement that follows a standardised procedure which is less open to subjective interpretation by potentially biased observers and study participants.
  • Off-label prescribing

    A drug or device prescribed to treat a condition or disease for which it is does not have UK marketing authorisation.
  • 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 a healthcare intervention is the 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.
  • 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 multiple technology appraisal or interventional procedures guidance. It is used to inform support the Appraisal Committee or Interventional Procedures Advisory Committee in making draft recommendations about the drug, treatment or procedure.
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