MEASUREMENT OF DISABILITY ADJUSTED LIFE YEAR (DALY) IN ENVIRONMENTAL ECONOMICS

B.S. CHAITRA

September 28, 2003

It has long been recognized that the environment in which people live-from the household to the global level-significantly affects their health. Measuring and valuing the health impacts of pollution are very complex and available methods of analysis are often rudimentary.

In recent years, quantitative estimates of the impact of environmental risks on health have emerged in the course of research on the global burden of disease, which uses a standardized measure of health outcomes, Disability adjusted life years (DALYs) across various causes of illness and death which has been launched by the World Bank.

DALYs combine life-years lost due to premature death and fractions of years of healthy life lost as a result of illness or disability.

Adding these two numbers produces a single measure, the DALY. One DALY is thus one lost year of healthy life. The total DALYs in a population in any given year indicates that population's disease burden for that year.

This seminar describes the values incorporated in the DALY indicator and methodology used in WDR to calculate DALYs for each of these four scenarios. Case 1:DALYs lost due to immediate death. Case 2: DALYs lost due to death following disability. Case 3: DALYs lost due to permanent disability. Case 4: DALYs lost due to disability followed by complete recovery.

References

• David Kay, Annette Pruss and Carlos Corvalan, 2000, Methodology for assessment of environmental burden of disease: Report on the ISEE Session on environmental burden of disease.


• Maureen Cropper, 2002, Risk assessment: alternative approaches. Working paper, The World Bank. Washington, D.C


• Morrow, Richard, H., and Bryant John, H., 1995, Health policy approaches to measuring and valuing human life: Conceptual and ethical issues. American Journal of Public Health, 85(10): 1336-1360