Healthy Life Expectancy

Concept

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Theoretically, Healthy Life Expectancy (HALE) is a summary population health measure that estimates the average number of years an individual can expect to live in full health by accounting for years lived in states of less than full health due to disease and injury. It combines mortality and morbidity into a single metric and is grounded in life table analysis and burden of disease methodology. The concept exists to quantify both longevity and health-related quality of life at the population level.

Mathematically, Healthy Life Expectancy is estimated by adjusting conventional life expectancy using age-specific prevalence of health states weighted by disability or health utility. The most widely recognised approach is Sullivan's method, which incorporates disability weights into standard life tables to estimate expected years lived in healthy and unhealthy states.

In practice, Healthy Life Expectancy is calculated using national mortality statistics, census data, health surveys and disability weights derived from burden of disease studies. It is widely used by governments, the World Health Organization and health economists to evaluate population health, compare countries, assess health inequalities and estimate the long-term benefits of healthcare interventions and public health policies.

Purpose

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Used to quantify population health by combining mortality and morbidity, compare health outcomes across populations, evaluate health policies and support health economic and public health decision-making.

Mathematical Formulae

Primary Formula

HALE = �(Lx ? (1 ? DWx)) � l?

where:

• Lx = person-years lived within age interval x
• DWx = average disability weight for age interval x
• l? = number of survivors at birth in the life table

Supporting Formulae

Healthy Years = Life Expectancy ? Years Lived with Disability

Expected Healthy Person-Years = Lx ? (1 ? DWx)

Related Mathematical Methods

• Sullivan method
• Life table analysis
• Disability-adjusted life year (DALY) estimation
• Multi-state life table modelling
• Survival analysis
• Burden of disease modelling

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Example

A life table estimates that a population has a life expectancy of 82 years. After adjusting each age interval using disability weights, the total expected healthy years equal 72.4 years.

HALE = 72.4 years

The population therefore has a Healthy Life Expectancy of 72.4 years, indicating that an average individual is expected to live approximately 72 years in full health.

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Excel Implementation

Function	Example Formula	Health Economics Application
SUMPRODUCT	=SUMPRODUCT(B2:B101,C2:C101)	Calculate disability-adjusted healthy person-years across age groups.
SUM	=SUM(D2:D101)	Calculate total healthy person-years.
Division	=SUM(D2:D101)/B2	Calculate Healthy Life Expectancy from the life table.
IF	=IF(E2<70,"Below Benchmark","Meets Benchmark")	Compare HALE with policy targets.
AVERAGE	=AVERAGE(E2:E21)	Calculate average HALE across regions or countries.

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VBA (Optional)

Automate Healthy Life Expectancy calculations from life tables, disability weight datasets and population statistics while generating comparative population health reports.

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Sources

• World Health Organization. World Health Statistics.
• Murray CJL, Salomon JA, Mathers CD, Lopez AD. Summary Measures of Population Health.
• Sullivan DF. A Single Index of Mortality and Morbidity. HSMHA Health Reports. 1971.
• Global Burden of Disease Study. Methods and Results.
• 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.