GeraClinic / NHS Waiting Times Index / Methodology

How the Gera NHS Waiting Times Index is calculated

The Gera NHS Waiting Times Index is a reproducible 0–100 score derived entirely from the real NHS England Referral-to-Treatment (RTT) release. This page sets out the exact formula, the weights, the single editorial constant, a worked example, the data provenance and the limitations — so anyone can reproduce or challenge the number.

What the index measures

The index answers one question: how far are NHS England elective waiting times from the standard patients are entitled to? It blends two official NHS accountability metrics into a single 0–100 number, where 100 means the 18-week standard is met with nobody waiting over a year, and lower means longer waits. It is published nationally, for 23 NHS treatment functions and 7 NHS England regions, so the same number is comparable across every cut.

The formula

1. Standard component (S) — weighted 80%

The share of incomplete pathways seen within 18 weeks, expressed against the NHS Constitution’s 92% standard — that at least 92% of patients on an incomplete RTT pathway should be waiting no more than 18 weeks. This is a legal standard, not an editorial choice, so there is no arbitrary constant here.

S = min(100, pctWithin18 / 92 × 100)

2. Long-wait component (L) — weighted 20%

The share of the list still waiting more than 52 weeks, scored against a 5% zero-tolerance reference ceiling. This 5% figure is the only editorial constant in the index: it is the 52+-week share at which the long-wait component scores zero. The NHS ambition is that nobody waits more than a year, so a 0% long-wait share scores 100.

share52 = over52Weeks / totalIncomplete
L = max(0, 100 × (1 − min(1, share52 / 0.05)))

3. The blended index (GNWI)

GNWI = 0.8 × S + 0.2 × L (rounded to 1 dp)

The 0.8/0.2 weighting is a documented Gera editorial choice: the headline 18-week standard dominates, and the year-plus long-wait tail acts as a severity modifier. Higher = shorter waits.

Worked example — England, April 2026

Within 18 weeks: 64.9% of 7,123,980 pathways
Waiting over 52 weeks: 100,665 (1.4% of the list)
S = min(100, 64.9 / 92 × 100) = 70.5
L = max(0, 100 × (1 − 1.4% / 5%)) = 71.7
GNWI = 0.8 × 70.5 + 0.2 × 71.7 = 70.8 / 100

Median wait for context: 11.9 weeks (not an input to the index; shown alongside because it is the figure most patients recognise).

Data provenance

Every figure the index consumes is taken directly from the NHS England Consultant-led RTT waiting-times release. National and per-specialty figures use the provider-based full extract; the regional split uses the commissioner-based file from the same monthly release. No value is estimated or imputed; the index is the only Gera-computed layer, and it is fully specified above.

Contains public sector information published by Gera Systems and licensed under the Open Government Licence v3.0 (source data). Source: Gera NHS Waiting Times Index — derived from NHS England RTT open data (April 2026, published 19 June 2026).

What the index does NOT show

It covers England only, and only consultant-led elective (RTT) waits to start treatment.
It excludes A&E, cancer 62-day, diagnostic, mental-health talking-therapy, GP and dental waits — those have separate Gera data pages.
It is national, regional and specialty-level — not provider- or hospital-level, and not your personal wait.
The 18-week standard and the 5% long-wait ceiling are accountability benchmarks, not clinical urgency thresholds; a clinically urgent case is prioritised regardless of the list.
The index is a summary measure. For any decision about your own care, check with your NHS provider — this page is information, not medical advice.

Update cadence

NHS England publishes RTT waiting-times data monthly, roughly six weeks after the reference month. Gera recomputes the index on each release. The figures here are for April 2026 and were last recomputed on 19 June 2026.

← Back to the Gera NHS Waiting Times Index

Contains public sector information published by NHS England and licensed under the Open Government Licence v3.0. Source: NHS England — Consultant-led Referral to Treatment (RTT) Waiting Times (April 2026, published June 2026). Licensed under the Open Government Licence v3.0. This directory is not affiliated with NHS England.