Concept Architecture
Concept
Theoretically, YLL Calculation is the method used to quantify premature mortality by estimating the number of Years of Life Lost (YLL) due to death occurring before a standard life expectancy. It forms one of the two components of the Disability-Adjusted Life Year (DALY) framework developed for the Global Burden of Disease study. YLL calculation exists to measure the mortality burden of disease in a consistent and comparable manner across populations.
Mathematically, YLL is calculated by multiplying the number of deaths attributable to a condition by the standard remaining life expectancy at the age of death. The resulting value represents the total number of years of expected life lost because of premature mortality.
In practice, YLL is calculated using mortality data from vital registration systems, disease registries or epidemiological surveillance together with standard life tables. The resulting estimates are incorporated into burden of disease studies, DALY calculations, priority setting and public health policy evaluation.
Purpose
Used to quantify premature mortality, estimate the mortality burden of disease, calculate Disability-Adjusted Life Years, compare diseases across populations and support health policy, priority setting and economic evaluation.
Mathematical Formulae
Primary Formula
YLL = N ? L
where:
- N = number of deaths
- L = standard remaining life expectancy at the age of death
Supporting Formulae
For multiple age groups:
YLL = ????? N?L?
where:
- N? = number of deaths in age group i
- L? = standard remaining life expectancy for age group i
Related Mathematical Methods
- Disability-Adjusted Life Year (DALY) calculation
- Burden of disease analysis
- Life table analysis
- Mortality analysis
- Epidemiological modelling
Example
A disease causes 40 deaths among individuals with a remaining standard life expectancy of 28 years.
YLL = 40 ? 28 = 1,120
The disease contributes 1,120 Years of Life Lost due to premature mortality.
If deaths occur across multiple age groups, YLL is calculated separately for each group and then summed to obtain the total YLL.
Excel Implementation
| Function | Example Formula | Health Economics Application |
|---|---|---|
| PRODUCT | =B2*C2 | Calculate YLL for a single age group |
| SUMPRODUCT | =SUMPRODUCT(B2:B20,C2:C20) | Calculate total YLL across multiple age groups |
| SUM | =SUM(D2:D20) | Aggregate YLL across diseases or populations |
| XLOOKUP | =XLOOKUP(A2,LifeTable!A:A,LifeTable!B:B) | Retrieve standard remaining life expectancy from a life table |
VBA (Optional)
Automate the calculation of Years of Life Lost across multiple diseases, age groups and reporting periods using standard life tables.
Sources
- Murray CJL, Lopez AD, editors. The Global Burden of Disease. Harvard School of Public Health.
- Murray CJL, Acharya AK. Understanding DALYs. Journal of Health Economics. 1997.
- Global Burden of Disease Collaborative Network. Global Burden of Disease Study Methods.
- World Health Organization. Global Health Estimates: Methods and Data Sources.
- Drummond MF, Sculpher MJ, Claxton K, Stoddart GL, Torrance GW. Methods for the Economic Evaluation of Health Care Programmes. Oxford University Press.
Related Concepts (2)
Library
Media
1
What is Health Economics? — Introductory Explainer — (Educational), 2017 (YouTube)
A concise explainer introducing why health economics matters for global and public health decision-making, including how DALYs are calculated and used to compare interventions.
Video (YouTube)View source →
Frequently Asked Questions (6)
What is a yll calculation?
The process of computing years of life lost by summing, across all deaths from a cause, the gap between age at death and standard life expectancy.
Source: Murray 1994
What does YLL calculation compute?
Years of life lost calculation computes the fatal health loss from a cause by summing, over all deaths from it, the years each death removed relative to the life expectancy remaining at the age of death. A death at a younger age contributes more years than a death at an older age. The total measures how much life a cause takes prematurely, forming the mortality component of the disability-adjusted life year and expressing deaths in units of time rather than counts.
Source: Murray 1994
What inputs does YLL calculation require?
The calculation requires the number of deaths from a cause by age, and a standard life expectancy at each age of death against which the loss is measured. Multiplying the deaths at each age by the expectancy remaining at that age, and summing across ages, gives the years of life lost. Reliable cause-of-death data and an agreed reference life table are therefore needed, since the estimate depends on both the counts and the expectancy figures used.
Source: Murray 1994
Why use a standard life expectancy in YLL calculation?
A common reference life expectancy is used so that a death at a given age is counted the same wherever it occurs, allowing burden to be compared across populations without penalising those with lower local life expectancy. Using each population's own life table would attribute fewer lost years to deaths in places where people already die younger, understating their loss. A single aspirational standard treats the years lost by a death at a given age as equal everywhere.
Source: Murray 1994
What choices affect YLL calculation?
The reference life expectancy chosen affects the totals, since a more generous standard attributes more years to each death. Earlier burden studies also applied age weighting, which valued years in middle age above those in infancy and old age, and discounting of future years, both of which changed the totals and have since been dropped in some studies. Because these conventions alter results, comparisons across studies require that the same choices were made.
Source: Murray 1994
How does YLL calculation combine with years lived with disability?
The years of life lost from mortality are added to the years lived with disability from non-fatal illness to give disability-adjusted life years, a single measure of the burden of a cause. Years of life lost capture the loss from premature death, and years lived with disability the loss from time spent in poor health. Adding them lets causes that mainly kill and those that mainly disable be compared on one scale and ranked by total burden.
Source: Murray 1994
Trust Record
Verified by Dr Darrin Baines
British health economist
Professional identity: darrinbaines.org
Verification date: 13 Aug 2025
Content version: 1.0.0
Canonical Identity
- Persistent URI
- https://healtheconomics.wiki/concept/yll-calculation
- Term code
- HE-EE-DALY-010
Stable URI · Machine-readable · Resolvable · CC BY 4.0