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.
The p value is a statistical measure that indicates whether or not an effect is statistically significant.
For example, if a study comparing 2 treatments found that 1 seems to be more effective than the other, the p value is the probability of obtaining these results by chance. By convention, if the p value is below 0.05 (that is, there is less than a 5% probability that the results occurred by chance), it is considered that there probably is a real difference between treatments. If the p value is 0.001 or less (less than a 0.1% probability that the results occurred by chance), the result is seen as highly significant. However, a statistically significant difference is not necessarily clinically significant. For example, drug A might relieve pain and stiffness statistically significantly more than drug B. But, if the difference in average time taken is only a few minutes, it may not be clinically significant. See Minimal clinically important difference.
If the p value shows that there is likely to be a difference between treatments, the confidence interval describes how big the difference in effect might be.
A way for pharmaceutical companies to make high-cost drugs affordable for the NHS. Companies may submit a patient access scheme proposal for any technology going through the NICE single or multiple technology appraisal processes, and highly specialised medicines process. For example, the company might pay for the drugs for an introductory period for each patient, and then the NHS would take over the payments if the drug is shown to work for that person; or the NHS might pay for the first course of a drug and the company would take over the payments if the patient needs treatment for longer than average.
Each proposal is assessed by the Patient Access Scheme Liaison Unit.
A tool that presents evidence-based estimates of the benefits and risks of the available treatment options in sufficient detail that people are better able to judge their value. In contrast to health education materials, PDAs are tailored to a person’s health status and help them to make specific, personal choices about their treatment. The values and perceptions of individual people, and their attitudes to risk, may be different from those of their clinician. Importantly, PDAs are intended to supplement or support the interaction between the person and their clinician, rather than replace it.
A comparison of treatment groups in a trial that includes only those patients who completed the treatment they were originally allocated to. If done alone, this analysis leads to bias.
A structured approach for developing review questions that divides each question into 4 components: the population (the population being studied); the interventions (what is being done); the comparators (other main treatment options); and the outcomes (measures of how effective the interventions have been).
A fake (or dummy) treatment given to patients in the control group of a clinical trial. It is indistinguishable from the actual treatment (which is given to patients in the experimental group). The aim is to determine what effect the experimental treatment has had - over and above any placebo effect caused because someone has had (or thinks they have had) care or attention.
A group of people with a common link, such as the same medical condition or living in the same area or sharing the same characteristics. The population for a clinical trial is all the people the test or treatment is designed to help (such as adults with diabetes). The group of people taking part in a clinical trial need to be typical of the whole population of interest.
The proportion of people with a positive test result who actually have the disease or characteristic. It is different from sensitivity.
A document that summarises the findings from the evidence for a single technology appraisal. It is used to support the appraisal committee in their decision making about the drug, treatment or procedure.
How common a disease or condition is within a population, either at a point in time or over a given period of time (it includes new and existing cases). It is different from incidence.
NICE processes are the actions involved in producing NICE guidance or other advice or resources (such as tools to support implementation ). When producing NICE guidance, the process includes: deciding what it will cover (the scope), setting up a group of experts who will look at the evidence and make recommendations, and a consultation with professionals and the public on draft guidance.
A probable course or outcome of a disease. Prognostic factors are patient or disease characteristics that influence the course. Good prognosis is associated with a low rate of undesirable outcomes; poor prognosis is associated with a high rate of undesirable outcomes.
An observational study with 2 or more groups (cohorts) of people with similar characteristics. One group has a treatment, is exposed to a risk factor or has a particular symptom and the other group does not. The study follows their progress over time and records what happens.
A research study in which the health or other characteristic of patients is monitored (or 'followed up') for a period of time, with events recorded as they happen. This contrasts with retrospective studies.
The centre at NICE that produces guidelines on public health and social care topics based on the best available evidence. The primary role of these guidelines is to provide recommendations on ‘what works’ in terms of both the effectiveness and cost effectiveness of interventions and services. Public health topics include recommendations on health protection, health improvement, health promotion or service provision, and on both communicable and non-communicable diseases and conditions. Social care topics include recommendations about best practice, drawn from current evidence-based research, on care and support for people whose care is funded and organised by local authorities (including personal budgets), funded by local authorities by direct payments, or funded by the individual or their family (or a combination of these). The guidelines are developed by independent committees.
Advises NICE on involving patients, carers and the public in its work. It also supports patients, carers and members of the public who are involved in producing NICE guidance, and stakeholder organisations that contribute to NICE's work.
Publication bias occurs when researchers publish the results of studies showing that a treatment works well and do not publish those results showing it did not have any effect. If this happens, analysis of the published results will not give an accurate idea of how well the treatment works. This type of bias can be assessed by a funnel plot.