GeraClinic / Delayed Discharge Index / Methodology
How the Gera Delayed Discharge Index is calculated
The Gera Delayed Discharge Index is a reproducible 0–100 score derived entirely from the real NHS England Acute Discharge Situation Report. This page sets out the exact formula, the weights, the disclosed reference ceiling, 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 severe are hospital discharge delays — patients who are medically ready to leave but remain stuck in an acute bed? It blends two size-independent NHS rate metrics into a single 0–100 number, where 0 would mean almost everyone medically ready is discharged promptly with no long-stay tail, and higher means worse. It is published nationally, for 7 NHS England regions and 38 Integrated Care Boards, so the same number is comparable across every cut.
“No longer meets the criteria to reside” is the NHS operational test for a patient who is clinically ready to leave hospital. It is the successor to the discontinued Delayed Transfers of Care (DTOC) collection. The index uses only the published monthly aggregates — it never models an individual patient.
The formula
1. Throughput-shortfall component (S) — weighted 60%
Of the patients who no longer meet the criteria to reside, the share not discharged that day, scored against an 80% reference ceiling — the point at which this component maxes out. Four in five ready patients still stuck is a documented crisis level. This is a rate, so it does not reward or punish a system for its size.
shortfall = 1 − (discharged / NCTR)
S = min(100, shortfall / 0.8 × 100)
2. Chronicity component (C) — weighted 40%
Of all the additional (delayed) bed days contributed by patients with a length of stay of 7+ days, the share contributed by patients staying 21+ days — i.e. how entrenched the delays are. Because 21+ days is a subset of 7+ days, this ratio is between 0 and 1 by construction, so the natural ceiling is 1.0 and no editorial constant is needed.
chronicity = bd21plus / bd7plus
C = min(100, chronicity × 100)
3. The blended index (GDDI)
GDDI = 0.6 × S + 0.4 × C (rounded to 1 dp)
The 0.6/0.4 weighting is a documented Gera editorial choice: the day-to-day throughput failure is the headline, and the very-long-stay tail acts as a severity modifier. Higher = worse. The single reference ceiling (80% same-day shortfall) is the only editorial constant in the index; every other input is a published NHS number.
Worked example — England, May 2026
- Patients who no longer met the criteria to reside (month total): 694,275, of which 282,249 were discharged (40.7% discharged; 59.3% shortfall)
- Delayed bed days from 7+ day stays: 557,690, of which 464,850 came from 21+ day stays (83.4% chronicity)
- S = min(100, 0.593 / 0.8 × 100) = 74.2
- C = min(100, 0.834 × 100) = 83.4
- GDDI = 0.6 × 74.2 + 0.4 × 83.4 = 77.9 / 100
For context, NHS England valued the 412,026 delayed bed days in May 2026 at £231,558,612, using a reference unit cost of £562 per acute bed day. The cost figures are shown alongside the index but are not inputs to it.
Data provenance
Every figure the index consumes is taken directly from the NHS England Acute Discharge Situation Report (monthly). National figures use NHS England’s published England (Type 1 trusts) total; regional and ICB figures are the transparent monthly aggregates of the daily and weekly-snapshot tables in the same 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 NHS England and licensed under the Open Government Licence v3.0. Source: NHS England — Acute Discharge Situation Report (monthly) (May 2026, published 11 June 2026).
Contains public sector information published by Gera Systems and licensed under the Open Government Licence v3.0 (source data). Source: Gera Delayed Discharge Index — derived from the NHS England Acute Discharge Situation Report (May 2026, published 3 July 2026).
What the index does NOT show
- It covers England only, and only acute (Type 1 trust) discharge delays for adults 18+ — not paediatric, maternity or community-hospital delays.
- “No longer meets the criteria to reside” is an operational discharge standard, not a clinical-urgency judgement. Clinical decisions always take priority over the metric.
- The chronicity component uses weekly-snapshot bed-day figures; providers may choose which weeks they submit, so it is a robust aggregate rather than a continuous daily census.
- The index does not tell you about any individual patient’s care, and it does not attribute blame to a hospital, an ICB or social care — delays usually depend on services outside the hospital.
- This page is information, not medical advice. For any decision about your own care, use NHS 111 or speak to a clinician.
Update cadence
NHS England publishes the Acute Discharge Situation Report monthly. Gera recomputes the index on each release. The figures here are for May 2026 and were last recomputed on 3 July 2026.