Concept Architecture
Concept
Theoretically, Years of Life Lost (YLL) is a summary measure of premature mortality that quantifies the number of years lost due to death occurring before a specified reference life expectancy. It is a core component of burden of disease methodology and reflects the societal impact of premature death by assigning greater weight to deaths occurring at younger ages. The concept is grounded in life table analysis and population health measurement and exists to quantify mortality burden beyond simple death counts.
Mathematically, Years of Life Lost is calculated by multiplying the number of deaths at each age by the remaining standard life expectancy at the age of death and summing these values across all deaths. The measure is additive across diseases, causes of death and populations, making it suitable for national and international comparisons of disease burden.
In practice, Years of Life Lost is calculated using mortality records and standard reference life tables, such as those developed for the Global Burden of Disease Study. It is widely used by governments, the World Health Organization and health economists to estimate disease burden, prioritise healthcare resources, evaluate prevention strategies and calculate Disability-Adjusted Life Years (DALYs).
Purpose
Used to quantify premature mortality, estimate disease burden, prioritise health interventions, compare causes of death and support burden of disease and health economic analyses.
Mathematical Formulae
Primary Formula
YLL = �(Ni ? Li)
where:
- Ni = number of deaths at age i
- Li = standard remaining life expectancy at age i
Supporting Formulae
Individual YLL = Standard Life Expectancy ? Age at Death
Total YLL = � Individual YLL
Related Mathematical Methods
- Disability-Adjusted Life Year (DALY)
- Life table analysis
- Burden of disease modelling
- Standard life expectancy estimation
- Age standardisation
- Survival analysis
Example
A disease causes:
- 8 deaths at age 50, with a remaining standard life expectancy of 32 years
- 5 deaths at age 70, with a remaining standard life expectancy of 15 years
YLL = (8 ? 32) + (5 ? 15)
= 256 + 75
= 331 years
The disease therefore results in 331 Years of Life Lost, representing the burden of premature mortality within the affected population.
Excel Implementation
| Function | Example Formula | Health Economics Application |
|---|---|---|
| SUMPRODUCT | =SUMPRODUCT(B2:B101,C2:C101) | Calculate total Years of Life Lost across age groups. |
| SUM | =SUM(D2:D101) | Calculate total premature mortality burden. |
| IF | =IF(E2>1000,"High Burden","Lower Burden") | Compare YLL with policy thresholds. |
| AVERAGE | =AVERAGE(E2:E21) | Calculate average YLL across regions or diseases. |
| Pivot Table | Aggregate deaths by age group | Produce age-specific YLL estimates. |
VBA (Optional)
Automate Years of Life Lost calculations using mortality datasets and standard life tables while generating burden of disease reports by cause, age group and geographic region.
Sources
- Murray CJL, Lopez AD. The Global Burden of Disease.
- World Health Organization. Global Health Estimates: Methods and Data Sources.
- Global Burden of Disease Study. Methods and Results.
- Devleesschauwer B, et al. Calculating Disability-Adjusted Life Years to Quantify Burden of Disease.
- Drummond MF, Sculpher MJ, Claxton K, Stoddart GL, Torrance GW. Methods for the Economic Evaluation of Health Care Programmes.
- Briggs A, Claxton K, Sculpher M. Decision Modelling for Health Economic Evaluation.
Related Concepts (2)
Library
Publications
1
Health at a Glance 2023: OECD Indicators — Organisation for Economic Co-operation and Development, 2023 Edition ed., 2023 (OECD Publishing)
OECD’s comprehensive biennial compendium of comparative indicators on population health and health-system performance across member and partner countries — health status, risk factors, access, quality, resources and spending — the standard cross-country benchmarking reference.
Frequently Asked Questions (6)
What is years of life lost?
A premature mortality measure calculated as the difference between age at death and a reference life expectancy, summed across deaths from a cause.
Source: Murray 1994
What premature mortality does years of life lost measure?
Years of life lost is a measure of premature mortality. It is calculated as the difference between the age at which a person died and a reference life expectancy, summed across all deaths from a cause. It measures how much life was cut short, weighting a death more heavily the younger it occurs. It uses a reference life expectancy as its yardstick, the age to which the person might otherwise have lived. It feeds disease burden, contributing the premature-death component that combines with disability to give the total burden. Life cut short by early death is what it measures. Murray (1994) set this out.
Source: Murray 1994
How is years of life lost calculated?
Years of life lost is calculated as the difference between age at death and a reference life expectancy, summed across deaths from a cause, so each death's gap from the reference is added up. This calculation defines it. So years of life lost is a premature mortality measure calculated as the difference between age at death and a reference life expectancy, summed across deaths from a cause.
Source: Murray 1994
What does years of life lost measure?
Years of life lost measures premature mortality, so it captures how much life is lost early by taking the difference between age at death and a reference life expectancy, summed across deaths from a cause. This measurement of premature mortality defines it. So years of life lost is a premature mortality measure calculated as the difference between age at death and a reference life expectancy, summed across deaths from a cause.
Source: Murray 1994
What reference does years of life lost use?
Years of life lost uses a reference life expectancy, so it compares age at death against that reference, taking the difference and summing it across deaths from a cause. This reference life expectancy defines part of the calculation. So years of life lost is a premature mortality measure calculated as the difference between age at death and a reference life expectancy, summed across deaths from a cause.
Source: Murray 1994
How does years of life lost relate to disease burden?
Years of life lost relates to disease burden as a component of it: disease burden is the total impact of a disease on a population covering mortality, morbidity, and costs, and years of life lost is a premature mortality measure summing the gap between age at death and a reference life expectancy. So years of life lost captures the premature-death part of disease burden, connected as a measure feeding the mortality component of total impact.
Source: Murray 1994
Trust Record
Verified by Dr Darrin Baines
British health economist
Professional identity: darrinbaines.org
Verification date: 11 Mar 2026
Content version: 1.0.0
Canonical Identity
- Persistent URI
- https://healtheconomics.wiki/concept/years-of-life-lost
- Term code
- HS-HP-PHO-017
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