Health-Adjusted Life Year

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Introduction & definition

Health-Adjusted Life Years are a measurement of the health of a population, typically used in estimates of the burden of disease.

HALYs are used to measure the combined effects of mortality and morbidity in populations; they permit comparisons between illnesses or interventions as well as between populations[1]

They are commonly used to compare the cost-effectiveness of different health interventions.

Calculation of HALY

The two most common ways of measuring HALYs are:

Function/Uses of HALYs

HALYs are based on the latest available epidemiological data, and the accuracy & usefulness of the HALY measurement depends on the completeness & accuracy of the data used.

Data can be taken from a variety of sources, including: census & national surveillance data; hospital records; surveys (eg. road safety surveys, or health surveys); police records; mortuary records; death certificate information.

Ideally the data should all be recent, locally derived and disaggregated by age and sex.


  1. Gold, MR, Stevenson D, Fryback DG. HALYs and QALYs and DALYs, Oh My: similarities and differences in summary measures of population Health. Annu Rev Public Health, 2002; 23:115-34