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.

  • QALY

    See quality-adjusted life year.
  • Qualitative research

    Qualitative research explores people's beliefs, experiences, attitudes, behaviour and interactions. It asks questions about how and why. For example, why people want to stop smoking, rather than asking how many people have tried to stop. It generates non-numerical data, such as a person's description of their pain rather than a measure of pain. Qualitative research techniques such as focus groups and in depth interviews may be used when developing NICE guidance to find out more about the views and experiences of the target population or practitioners.
  • Quality and Outcomes Framework (QOF)

    A national incentive scheme for all GP practices in the UK, which rewards them financially for how well they care for patients. Under the scheme, GP practices score points according to their level of achievement against a series of indicators, such as the percentage of patients with a new diagnosis of a disease who are referred for certain tests. NICE makes sure the clinical and health improvement indicators used in the scheme reflect new evidence and rising service standards.
  • Quality standards

    NICE quality standards are a set of specific, concise statements and associated measures. They set out aspirational, but achievable, markers of high-quality, cost-effective patient care, covering the treatment and prevention of different diseases and conditions. They are based guidance and advice from NICE and other organisations using NICE-accredited processes.
  • Quality statement

    Five to 10 quality statements make up a quality standard. The statements describe key markers of high-quality, cost-effective care for a particular clinical condition or pathway. An example of a quality statement for stroke is:
    'All patients after stroke are screened within 6 weeks of diagnosis, using a validated tool, to identify mood disturbance and cognitive impairment'.
  • Quality-adjusted life year (QALYS)

    A measure of the state of health of a person or group in which the benefits, in terms of length of life, are adjusted to reflect the quality of life. One QALY is equal to 1 year of life in perfect health.
    QALYs are calculated by estimating the years of life remaining for a patient following a particular treatment or intervention and weighting each year with a quality of life score (on a zero to 1 scale). It is often measured in terms of the person's ability to perform the activities of daily life, freedom from pain and mental disturbance.
  • Quantitative research

    Research that generates numerical data or data that can be converted into numbers. An example is research using clinical trials. Another example is the national Census, which counts people and households. It might involve questions such as 'How many people visit their GP each year?' or 'What proportion of children have had this vaccine?'.
  • Quasi-experimental study

    A study based on a true experimental design meets 2 criteria: manipulation of a variable factor between 2 or more groups, and random assignment of participants to those groups. A quasi-experimental study uses the first criterion but participants are not randomly assigned to groups. This means a researcher can't draw conclusions about 'cause and effect'. This design is frequently used when it is not feasible, or not ethical, to conduct a randomised controlled trial. See also experimental study.
  • Quorum

    The smallest number of group members that must be present to constitute a valid meeting.
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