Can I reproduce the Gera Healthy-Place Index myself?

Yes. Download the three source datasets (DEFRA UK-AIR Local Authority annual mean PM2.5 and NO2 2024; ONS life expectancy at birth; CQC GP-practice ratings), join them at upper-tier local-authority level, min-max normalise each pillar 0–100 across the included areas, then apply the published weights. Every figure is real and unaltered.

Why is the index computed at upper-tier local-authority level?

The three datasets are published at different tiers, and the upper-tier local authority (county & unitary) is the finest geography on which all three resolve with full coverage. DEFRA district figures are rolled up to the upper-tier authority by taking the maximum across constituent districts; life expectancy and CQC GP ratings are already published at this tier.

How are weights chosen, and can I change them?

The default weights (40% air, 35% life expectancy, 25% GP access) are a documented Gera editorial choice, not derived from the data. The interactive tool lets you re-weight the three pillars and re-rank every area to your own priorities.

Gera Healthy-Place Index — Methodology

The Gera Healthy-Place Index (GHPI / 100) is a transparent composite of three real, free government datasets. Every figure is reproducible.

The formula

GHPI = 0.4 × air + 0.35 × longevity + 0.25 × gpAccess

where, normalised 0–100 across the 145 included areas:
  air        = minmax( −(max PM2.5 + max NO2) )      cleaner air → higher
  longevity  = minmax( (LE male + LE female) / 2 )   longer life → higher
  gpAccess   = minmax( % GP practices Good/Outstanding )  higher → higher

minmax(x) = 100 × (x − min) / (max − min)

The three pillars

Gera Healthy-Place Index pillars, weights and sources
Pillar	Weight	Real metric	Source
Air quality (DEFRA)	40%	Max annual-mean PM2.5 + NO2 (μg/m³), 2024	DEFRA UK-AIR
Life expectancy (ONS)	35%	Life expectancy at birth (combined), years	ONS
GP access (CQC)	25%	% GP practices rated Good or Outstanding	CQC

Air-quality context: the WHO 2021 annual-mean guidelines are 5 μg/m³ (PM2.5) and 10 μg/m³ (NO2); the UK statutory limit values are 20 μg/m³ and 40 μg/m³.

The join

The three datasets are published at different tiers. They are reconciled to the upper-tier local authority (county & unitary, ONS December 2024). DEFRA district figures are rolled up to the parent upper-tier authority by taking the maximum modelled annual mean across its districts (the worst-area exposure DEFRA reports for compliance). An area is included only when all 3 pillars resolve — 145 of 153 English upper-tier local authorities have all 3 pillars. The healthiest-ranked area is Rutland (92.9/100); the lowest is Manchester (27.1/100).

Areas excluded for full transparency

Upper-tier authorities excluded (a pillar lacks a real published value)
Local authority	Missing pillar(s)
Isles of Scilly	Life expectancy (ONS)
North Northamptonshire	Life expectancy (ONS)
West Northamptonshire	Life expectancy (ONS)
Cumberland	Life expectancy (ONS)
Westmorland and Furness	Life expectancy (ONS)
North Yorkshire	Life expectancy (ONS)
Somerset	Life expectancy (ONS)
City of London	Life expectancy (ONS)

These areas are excluded — never assigned an estimated or zero value. Most are absent because the ONS life-expectancy release pre-dates their 2021–2023 boundary reorganisation.

Sources

Air quality (DEFRA): DEFRA UK-AIR — Air quality annual mean by Local Authority (NO2 & PM2.5), 2024 (Department for Environment, Food & Rural Affairs (DEFRA), 2024 calendar year; Open Government Licence v3.0)
Life expectancy (ONS): Office for National Statistics — Life expectancy by local authority + Health state life expectancies (Healthy life expectancy), UK (Office for National Statistics, 2017-19; Open Government Licence v3.0)
GP access (CQC): Care Quality Commission (CQC) — Care directory with ratings (Care Quality Commission, 2026-06-01; Open Government Licence v3.0)

Methodology: frequently asked questions

Can I reproduce the Gera Healthy-Place Index myself?: Yes. Download the three source datasets (DEFRA UK-AIR Local Authority annual mean PM2.5 and NO2 2024; ONS life expectancy at birth; CQC GP-practice ratings), join them at upper-tier local-authority level, min-max normalise each pillar 0–100 across the included areas, then apply the published weights. Every figure is real and unaltered.
Why is the index computed at upper-tier local-authority level?: The three datasets are published at different tiers, and the upper-tier local authority (county & unitary) is the finest geography on which all three resolve with full coverage. DEFRA district figures are rolled up to the upper-tier authority by taking the maximum across constituent districts; life expectancy and CQC GP ratings are already published at this tier.
How are weights chosen, and can I change them?: The default weights (40% air, 35% life expectancy, 25% GP access) are a documented Gera editorial choice, not derived from the data. The interactive tool lets you re-weight the three pillars and re-rank every area to your own priorities.
Which areas are excluded and why?: 145 of 153 English upper-tier local authorities have all 3 pillars. 8 English upper-tier authorities are excluded because the ONS life-expectancy release pre-dates their 2021–2023 boundary reorganisation (e.g. Isles of Scilly, North Northamptonshire, West Northamptonshire, Cumberland). They are listed transparently and never assigned an estimated value.

Contains public sector information published by Gera Systems and licensed under the Open Government Licence v3.0 (source data). Source: Gera Healthy-Place Index — composite of DEFRA + ONS + CQC open data (Air 2024 calendar year; life expectancy 2017-19; GP ratings 2026-06-01, published 19 June 2026).