Glossary
NHS waiting times glossary
Plain-English definitions of the 50 NHS waiting-time terms that come up most often on HospitalWaits. Every entry links to its official NHS or government source where one exists.
Written and reviewed by Mustafa Ghafouri (MBChB, MSc) · · Data through May 2026
Why this glossary exists
NHS waiting-time discussion is full of acronyms — RTT, DM01, FDS, ICB, TFC. The same letters mean different things to clinicians, commissioners and patients, and the official NHS guidance is written for a system audience. This page gives one plain-English definition per term, with the canonical source link where one exists.
These terms appear throughout HospitalWaits — on the trust pages, in the methodology, and in every statistical claim we make. If something on the site does not make sense, the definition is probably here. The entries are grouped below into 8 categories and listed alphabetically across the rest of the page.
- Standards
- Statistical concepts
- Pathway terms
- Organisations
- Datasets
- Quality
- Patient rights
- Specialty codes
All terms, alphabetical
18-week target
Standards
The NHS England operational standard that 92% of patients on the Referral-to-Treatment (RTT) pathway should start treatment within 18 weeks of referral. Set out in the NHS Constitution. The 92% bar has not been met nationally since 2015.
Source: NHS Constitution for England. Related: % within 18 weeks by specialty.
2-week wait (2WW)
Standards
Older shorthand for the urgent suspected-cancer pathway: patients seen by a specialist within two weeks of GP referral. NHS England has replaced 2WW with the 28-day Faster Diagnosis Standard as the headline cancer measure, but the term is still in everyday clinical use.
28-day Faster Diagnosis Standard (28-day FDS)
Standards
The cancer waiting-time standard that 75% of patients referred on a suspected-cancer pathway should be told whether they have cancer or not within 28 days. Replaced the older 2-week wait as the lead cancer metric. Reported monthly through the Cancer Waiting Times (CWT) release.
31-day standard
Standards
The cancer pathway target that 96% of patients should start first definitive treatment within 31 days of the clinical decision to treat. Tracked through the Cancer Waiting Times release.
Source: NHS England — Cancer Waiting Times.
6-week diagnostic target
Standards
NHS England's aim that fewer than 1% of patients should wait six weeks or more for a diagnostic test such as MRI, CT, ultrasound or endoscopy. Performance against this target is reported every month in the DM01 release.
Source: NHS England — DM01 diagnostics.
62-day cancer standard
Standards
The cancer pathway target that 85% of patients urgently referred for suspected cancer should start first definitive treatment within 62 days of referral. The longest of the headline cancer standards and the hardest to hit nationally.
Source: NHS England — Cancer Waiting Times.
92% standard
Standards
Shorthand for the operational threshold inside the 18-week RTT target. NHS Constitution sets the standard that 92% of patients on an incomplete RTT pathway should be waiting fewer than 18 weeks at any point in time.
Source: NHS England — RTT statistics.
92nd percentile wait
Statistical concepts
The wait length at which 92% of patients are seen sooner. Used because the NHS Constitution sets the 92% bar inside 18 weeks. If the 92nd-percentile wait at a trust is 24 weeks, the trust is missing the 18-week standard for that specialty.
Related: How we calculate percentile waits.
Active monitoring
Pathway terms
A clinical decision to watch a patient's condition under specialist care rather than start active treatment immediately. Active monitoring stops the RTT clock when it is the chosen care plan, because the clinical pathway is considered to have reached its first definitive outcome.
Source: NHS England — RTT guidance.
Acute Trust
Organisations
An NHS Trust that runs hospitals providing emergency and elective inpatient care, outpatient clinics, and most diagnostic services. The default trust type for the elective waits reported on HospitalWaits.
Source: NHS England — health organisations. Related: All NHS trusts A–Z.
Cancer Waiting Times (CWT)
Datasets
The monthly NHS England statistical release that reports performance against cancer pathway standards including the 28-day Faster Diagnosis Standard, the 31-day decision-to-treatment standard, and the 62-day urgent-referral-to-treatment standard.
Source: NHS England — Cancer Waiting Times.
CCG (legacy)
Organisations
Clinical Commissioning Group. The local NHS planning bodies that bought hospital services for their populations between 2013 and June 2022. CCGs were abolished and their functions transferred to Integrated Care Boards (ICBs). The term still appears in historical datasets.
Source: NHS England — Integrated Care.
Censoring
Statistical concepts
A statistical adjustment for waits that have not yet ended at the time the data are pulled. Patients still on an open RTT pathway are censored — their wait so far is recorded but their final wait length is unknown. Censoring is why incomplete-pathway numbers differ from completed-pathway numbers.
Clock start
Pathway terms
The day the RTT clock begins. Usually the day a GP referral is received by the hospital, or the day a patient self-refers through an NHS service that allows it. All RTT wait measurements run from the clock-start date.
Source: NHS England — RTT guidance.
Clock stop
Pathway terms
The day the RTT clock ends. The most common stop reason is first definitive treatment. Other valid stop reasons include a decision not to treat, the patient declining treatment, or active monitoring as the chosen plan.
Source: NHS England — RTT guidance.
Closed pathway
Pathway terms
An RTT pathway whose clock has stopped. Closed pathways are reported either as admitted (the patient was admitted for treatment) or non-admitted (treatment was provided in an outpatient setting). Distinct from incomplete (still-open) pathways.
Source: NHS England — RTT statistics.
Cohort
Statistical concepts
A group of patients defined by a shared start point — typically all patients whose RTT clocks started in the same month, or all patients who completed treatment in the same month. Cohort framing matters because incomplete-pathway and completed-pathway numbers measure different things.
Community Trust
Organisations
An NHS Trust that provides care outside the acute hospital setting — community nursing, district services, intermediate care, some therapy services. Some elective specialties are reported via community trusts and appear in RTT alongside acute trusts.
Source: NHS England — health organisations.
Completed pathway
Pathway terms
An RTT pathway that has reached a valid clock stop. Reported in the RTT release split into admitted (patient admitted for treatment) and non-admitted (treatment provided without admission). Completed-pathway waits are the actual durations patients waited end-to-end.
Source: NHS England — RTT statistics.
CQC (Care Quality Commission)
Quality
The independent regulator of health and adult social care in England. CQC inspects providers and publishes ratings (Outstanding, Good, Requires Improvement, Inadequate) for each registered service.
Source: Care Quality Commission.
CQC rating
Quality
The single-word judgement assigned by the Care Quality Commission to a trust or service after inspection. Ratings are Outstanding, Good, Requires Improvement, or Inadequate. Trust-level ratings are aggregated from individual service-level ratings.
Source: Care Quality Commission.
Decision to treat
Pathway terms
The clinical decision that a patient needs a specific treatment. The decision-to-treat date is the start point for the 31-day cancer standard. On an RTT pathway, the decision to treat itself does not stop the clock — first definitive treatment does.
Source: NHS England — Cancer Waiting Times.
DM01
Datasets
The monthly NHS England statistical release that reports waits for 15 categories of diagnostic test, including MRI, CT, ultrasound, endoscopy, audiology and sleep studies. Separate from RTT — RTT covers consultant-led treatment, DM01 covers diagnostic tests.
Source: NHS England — DM01.
e-Referral Service (e-RS)
Patient rights
The national NHS service GPs use to book and refer patients to hospital appointments. e-RS is also the system through which Right to Choose works in practice — the GP searches alternative providers in e-RS and books the patient at their chosen hospital.
Source: NHS Digital — e-Referral Service. Related: How Right to Choose works.
FFT (Friends and Family Test)
Quality
A short feedback survey NHS patients are asked to complete after care. Asks whether the patient would recommend the service to friends and family. Published nationally each month as a patient-experience indicator.
First definitive treatment
Pathway terms
The first treatment that is intended to manage a patient's condition rather than diagnose it. Starting first definitive treatment is the most common reason an RTT clock stops. It may be surgery, but it is more often the start of medication, a procedural plan, or a structured monitoring programme under specialist care.
Source: NHS England — RTT guidance.
Foundation Trust
Organisations
A type of NHS Trust with greater financial and operational autonomy. Foundation Trusts are accountable to a council of governors elected by local members rather than directly to the Department of Health and Social Care. Clinical responsibilities are the same as non-foundation NHS Trusts.
Source: NHS England — health organisations.
GIRFT (Getting It Right First Time)
Quality
A national NHS England programme that uses peer-reviewed data to reduce unwarranted variation in clinical practice. GIRFT publishes specialty-level reports identifying outlier performance and recommending pathway changes.
Source: Getting It Right First Time.
GP Practice
Organisations
A general-practice surgery contracted to deliver NHS primary care. GP Practices are the entry point to most RTT pathways — the GP referral starts the clock. Practices are not trusts and do not directly appear in RTT data.
HES (Hospital Episode Statistics)
Datasets
The national dataset of completed admitted-patient, outpatient and accident-and-emergency activity in NHS hospitals in England. HES is collected by NHS England Digital and used for analytical and research purposes. RTT is built from HES-adjacent monthly collections rather than directly from HES.
Source: NHS Digital — HES.
ICB (Integrated Care Board)
Organisations
A statutory NHS body responsible for planning and buying NHS services for a defined geographic population. ICBs replaced Clinical Commissioning Groups (CCGs) in July 2022. There are 42 ICBs in England.
Source: NHS England — ICS / ICB. Related: ICB wait comparison.
ICS (Integrated Care System)
Organisations
A partnership of NHS and local-authority organisations covering a geographic area, responsible for planning health and care services together. The Integrated Care Board is the NHS statutory body within an ICS. The terms overlap in everyday use.
Source: NHS England — ICS / ICB.
Incomplete pathway
Pathway terms
An RTT pathway whose clock is still running at the snapshot date. The incomplete-pathway count is the NHS waiting list. Incomplete-pathway waits are how long each waiting patient has been waiting so far — not how long they will end up waiting.
Source: NHS England — RTT statistics.
ISP (Independent Sector Provider)
Organisations
A non-NHS organisation — usually private or third-sector — that delivers NHS-funded care under an NHS contract. Many ISPs report into RTT for the NHS-funded work they do. Patients exercising Right to Choose can in many cases choose an ISP as their hospital.
Source: NHS England — RTT statistics. Related: Right to Choose and ISPs.
KH06
Datasets
The legacy quarterly NHS England return that reported waits for outpatient referrals before the modern monthly RTT release replaced it in 2007. The term still appears in older guidance and historical comparisons.
Source: NHS England — RTT statistics.
Median wait
Statistical concepts
The middle wait length when every patient's wait is lined up shortest to longest. Half wait less, half wait more. A more honest single number than the mean because a few extremely long waits do not pull it upwards. The lead metric on HospitalWaits. Because RTT counts pathways that are still open, this is the wait so far of people currently on the list — not how long a new referral will ultimately wait, which is usually longer.
Related: How we calculate median waits.
Mental Health Trust
Organisations
An NHS Trust that provides mental health and learning-disability services. Some elective specialties (for example, child and adolescent mental health) are reported via mental health trusts. Their data structure follows the same RTT rules as acute trusts.
Source: NHS England — health organisations.
NHS Digital (now NHS England Digital)
Organisations
The national NHS body responsible for digital, data, and technology services. Formerly the Health and Social Care Information Centre, then NHS Digital, now part of NHS England as NHS England Digital after the 2023 merger. Custodian of HES, the e-Referral Service, and the Organisation Data Service.
Source: NHS England Digital.
NHS England (NHSE)
Organisations
The arm's-length public body that leads the NHS in England. Sets strategic direction, oversees commissioning, and publishes the national RTT, DM01 and Cancer Waiting Times statistics that HospitalWaits is built on.
Source: NHS England.
ODS (Organisation Data Service)
Datasets
The authoritative NHS Digital register of every NHS and care organisation in England, including trusts, GP practices and ICBs. Each organisation has a unique ODS code (for example, RJ1 for Guy's and St Thomas'). HospitalWaits keys trusts by ODS code throughout.
Open pathway
Pathway terms
A live RTT pathway whose clock has started but not yet stopped. Open and incomplete are used interchangeably in NHS guidance. The count of open pathways is the elective waiting list.
Source: NHS England — RTT statistics.
Pathway
Pathway terms
The sequence of NHS contacts associated with one patient's referral — from the first GP letter through outpatient appointments, diagnostics, decision to treat, and treatment. A single pathway has one clock; the clock starts on referral and stops at first definitive treatment or another valid clock-stop event.
Source: NHS England — RTT guidance.
Patient Choice
Patient rights
The NHS policy that gives patients the right to choose where they are treated for elective referrals. Patient Choice underpins the legal Right to Choose protections and is operationalised through the e-Referral Service.
Source: NHS.uk — choosing a hospital. Related: Exercise Right to Choose.
Referral-to-Treatment (RTT)
Pathway terms
The NHS England measure of how long patients wait between GP referral and the start of treatment for elective (non-emergency) care. The wait is measured in weeks. The RTT release is published monthly and covers every NHS hospital trust and treatment function in England.
Source: NHS England — RTT statistics. Related: What are NHS waiting times?.
Right to Choose
Patient rights
The legal right of NHS patients in England to choose where they go for a first outpatient referral. Patients can choose any provider that holds an NHS contract for the relevant service — including independent sector providers. Exercised through the e-Referral Service at the time of GP referral.
Source: NHS.uk — choosing a hospital. Related: Step-by-step guide.
Specialty
Specialty codes
A clinical area of practice — for example, cardiology, ophthalmology, trauma and orthopaedics. RTT is reported at specialty level using NHS Treatment Function Codes. HospitalWaits exposes the 18 user-facing specialties NHS England publishes individual trust-level RTT data for.
Source: NHS Data Dictionary — Treatment Function Code. Related: Browse specialties.
TFC (Treatment Function Code)
Specialty codes
The NHS Data Dictionary code identifying the specialty in which an episode of care was delivered. Three-character codes (for example, 100 for general surgery, 110 for trauma and orthopaedics, 130 for ophthalmology). RTT and HES data are keyed by TFC.
Source: NHS Data Dictionary — TFC.
Trim point
Statistical concepts
A wait-length cut-off used to exclude implausibly long or short pathways from a statistical summary. Trim points are used in HES analyses to keep medians stable when a small number of records carry data-quality errors. Different publications use different trim points; methodology pages document the choice.
Related: HospitalWaits methodology.
Trust
Organisations
A statutory NHS organisation that provides hospital, community or mental-health services to a defined population. A single trust often runs several hospital sites, so when HospitalWaits shows a wait for a “hospital” it is really the trust-wide median for that specialty across all of the trust's sites. England has around 215 NHS Trusts; HospitalWaits tracks the 538 provider organisations (including Foundation Trusts, Community Trusts, Mental Health Trusts and Independent Sector Providers) that submit RTT data each month.
Source: NHS England — health organisations. Related: All NHS trusts A–Z.
Waiting list
Pathway terms
The count of patients on an incomplete (still-open) RTT pathway at the snapshot date. The NHS waiting list reported in headlines is the sum of all incomplete RTT pathways across England — distinct from waiting time, which is how long each individual patient waits.
Source: NHS England — RTT statistics. Related: NHS waiting list explained.
Ready to compare
Find your wait at every NHS hospital near you
Search by postcode and specialty. Ranked by shortest wait. Free, independent, updated monthly.
Search NHS waits near youRelated
This page gives general information about NHS waiting-time terminology. It is not medical advice. For advice on your own case, speak to your GP or your consultant.