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.
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-adjusted life years (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 one 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 like: '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 two criteria: manipulation of a variable factor between two 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 and non-experimental study.
- Quick reference guide
A short, printed version of a NICE technology appraisal guidance, public health guidance or clinical guideline. This is designed for use by healthcare professionals and other staff who will be following the guidance. It contains the recommendations(or a summary of the recommendations) but not the supporting evidence.