Evidence, methods & authorship

Sources

The World Longevity Atlas is a compact, attributed derivative of official modelled estimates. Every view keeps its source, release, reference year and uncertainty visible; incompatible measures and denominators are not silently combined.

4: primary health-data sources
185: countries in the atlas
2000–2023: reference-year span

01 · Data

The data behind the atlas

Each source has a defined job. The labels below distinguish what the source covers from how the atlas uses it.

IHMEGBD 2023 Results

Causes of death & attributable risks

Used for: The exact-2023 cause distribution and risk-attributable burden rankings for selected GBD reference years.
Coverage: Twenty-one fatal Level-2 cause groups present in the mortality export for both sexes and all ages in 185 atlas countries; 20 Level-2 risk factors for both sexes and all ages. Source-published counts, shares and 95% uncertainty intervals are retained.
Boundary: The cause export does not support sex, age, crude-rate, YLL or age-standardised breakdowns. The full GBD hierarchy has 22 Level-2 clusters; the non-fatal Sense organ diseases cluster is absent from this mortality export. The atlas does not infer an additional row.
Export query: Causes: Deaths, Number and Percent, 2023, both sexes, all ages, Level 2. Risks: Deaths and DALYs, Number and Percent, all causes, both sexes, all ages, Level 2, for the displayed reference years. Input checksums are retained in the release manifest.

Global Burden of Disease Collaborative Network. Global Burden of Disease Study 2023 (GBD 2023) Results. Seattle, United States: Institute for Health Metrics and Evaluation (IHME), 2024. Available from https://vizhub.healthdata.org/gbd-results/.

Open the GBD Results Tool

United NationsWPP 2024

Demographic mortality & population

Used for: Exact-2023 all-cause deaths, population exposure and crude death rates for female, male and both-sex populations across all five atlas age selections.
Coverage: Source-published single-age deaths and population exposure, grouped into the atlas's age controls.
Boundary: These data are not combined with the GBD cause distribution to manufacture cause-specific rates or allocate causes.

United Nations, Department of Economic and Social Affairs, Population Division (2024). World Population Prospects 2024.

Open the dataset & documentation

The Lancet Public HealthGBD 2023 publication

Life expectancy & healthy life expectancy

Used for: Exact-2023 life expectancy and healthy life expectancy (HALE), including female, male and both-sex estimates.
Coverage: Open supplementary tables S1/S2, S4/S5 and S7/S8 for all 185 atlas countries, with source-published 95% uncertainty intervals.
Rights: The article and supplement are open access under CC BY 4.0. This does not replace the separate terms governing IHME Results Tool exports.

Hay SI, Nam P, Saqib H, et al. “Global, regional, and national trends in the morbidity gap and contributing diseases, injuries, and risk factors, 1990–2023.” The Lancet Public Health. 2026;11(8):e487–e505.

Open the article & supplement

World Health OrganizationGHE 2021

Historical mortality & longevity

Used for: Historical cause-specific mortality, years of life lost (YLL), life expectancy and HALE through 2021.
Coverage: WHO Global Health Estimates 2021 history from 2000–2021, preserving hierarchy, estimate type and available uncertainty.
Boundary: The 2021–2023 longevity segment is marked as a source change. No 2022 observation is inserted or inferred.

World Health Organization. Global Health Estimates 2021.

Open the dataset & methods

02 · Methods

Methods & interpretation

Values are modelled population-health estimates, not raw observations. The atlas preserves location, year, sex, age, measure, metric, hierarchy, release, estimate type and uncertainty wherever the source provides them.

Keep source domains separate

The exact-2023 view assigns a defined source to each domain: IHME for cause distribution and risks, UN WPP for demographic mortality, and the open GBD publication for longevity. Earlier years retain WHO GHE 2021. Cross-release changes may reflect methodology as well as population health.

Compare like with like

Country comparisons use the same year, sex, age selection and source on both sides. The 2023 cause percentages use the IHME GBD all-cause mortality envelope and are not divided by the UN WPP death total used in other demographic slices. Crude rates use the corresponding population; age-standardised rates are source-provided and are never inferred from crude rates.

Respect hierarchies

The 2023 cause ranking uses the 21 mutually exclusive fatal Level-2 groups present in the GBD mortality export. Historical WHO drill-downs show direct children for the active slice. A parent is never added to its descendants. Attributable risks may overlap, nest or mediate one another and are never summed into an all-risk total.

Frame longevity carefully

Healthspan is labelled healthy life expectancy (HALE). Life expectancy minus HALE is an equivalent population summary of years lived in less than full health. It is not a forecast that an individual will spend one continuous period ill.

Preserve uncertainty & provenance

Lower and upper uncertainty bounds must be both present or both absent and must contain the estimate. Missing intervals are reported as unavailable, not recreated. Release labels and source boundaries remain visible; the dotted 2021–2023 longevity segment makes the WHO-to-GBD transition explicit. Risk-attributable rows display their actual reference year when the nearest prior GBD year is used.

Underlying data quality varies

Comparability does not imply equal underlying data quality. Estimates for countries with limited vital registration, verbal-autopsy, survey or morbidity data depend more heavily on statistical modelling. Use the GBD Sources Tool to inspect available input-source metadata; the atlas does not currently calculate a country-level data-quality score.

This compact disclosure is informed by the GATHER reporting guidance: it identifies inputs, measures, source boundaries, uncertainty, transformation rules and reproducibility records without claiming that this interface is a full GATHER report.

Reading the atlas

Key terms

HALE: Healthy life expectancy.
YLL: Years of life lost through premature mortality.
DALY: Disability-adjusted life year: YLL plus years lived with disability.
ASR: Age-standardised rate per 100,000.
UI: Uncertainty interval around a modelled estimate.

Please read before using the atlas

Important disclaimer

The World Longevity Atlas is an independent informational project. It is not affiliated with, sponsored by, approved by or endorsed by the World Health Organization, the United Nations, IHME, The Lancet, Elsevier, OpenStreetMap, OpenFreeMap, MapLibre or any other data publisher or rights holder named here. All names, datasets, publications, trademarks and other intellectual property remain the property of their respective owners and are subject to their applicable terms.

This website is provided for general educational and exploratory purposes only. It is not medical advice, diagnosis, treatment, emergency guidance, clinical decision-support, public-health advice or a substitute for advice from a qualified professional. Do not use it to make decisions about an individual's care. For a medical emergency, contact the appropriate local emergency service.

The atlas uses modelled estimates and transformed source data. Despite reasonable efforts to preserve accuracy and provenance, the information may be incomplete, outdated, misinterpreted or incorrect and may contain source, processing, software or presentation errors. Estimates and historical series may change when publishers revise their data or methods. No representation or warranty, express or implied, is made as to accuracy, completeness, fitness for a particular purpose or availability.

Use of this website and reliance on its contents are at your own risk. To the maximum extent permitted by applicable law, the creator and contributors accept no liability for any loss, injury, damage, decision or action arising from its use or from reliance on its contents. To report a data, attribution or technical issue, contact g.ramponi@gmail.com.

03 · About

About the creator

Giacomo Ramponi

I'm an emergency medicine specialist based in Milan, working in a high-volume tertiary teaching hospital with complex and critically ill patients. Alongside clinical practice and research, I explore how thoughtful digital innovation and artificial intelligence can support safer, evidence-based care.

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Previous project · 2025

ResusBuddy

I founded and developed ResusBuddy, a multilingual resuscitation training tool for ACLS and PALS simulation. Built for practice across web and mobile, it helps learners rehearse high-stakes resuscitation pathways in a clear, structured format.

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