Disability-adjusted life years lost per 100,000 inhabitants in 2004:
  No data
  Fewer than 9,250
  9,250–16,000
  16,000–22,750
  22,750–29,500
  29,500–36,250
  36,250–43,000
  43,000–49,750
  49,750–56,500
  56,500–63,250
  63,250–70,000
  70,000–80,000
  More than 80,000

**Disability-adjusted life years** (**DALYs**) are a way of measuring the effects of diseases. They are calculated as the number of years lost due to ill-health, disability, or early death. It was developed in the 1990s as a way of comparing the overall health and life expectancy of different countries.

DALYs have become more common in the field of public health and health impact assessment (HIA). They include not only the potential years of life lost due to premature death but also equivalent years of 'healthy' life lost by virtue of being in states of poor health or disability. In so doing, mortality and morbidity are combined into a single, common metric.

Calculation
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adjusted life yearadjusted life year
Disability-adjusted life years are a societal measure of the disease or disability burden in populations. DALYs are calculated by combining measures of life expectancy as well as the adjusted quality of life during a burdensome disease or disability for a population. DALYs are related to the quality-adjusted life year (QALY) measure; however, QALYs only measure the benefit with and without medical intervention and therefore do not measure the total burden. Also, QALYs tend to be an individual measure and not a societal measure.

Traditionally, health liabilities were expressed using one measure, the years of life lost (YLL) due to dying early. A medical condition that did not result in dying younger than expected was not counted. The burden of living with a disease or disability is measured by the years lost due to disability (YLD) component, sometimes also known as years lost due to disease or years lived with disability/disease.

DALYs are calculated by taking the sum of these two components:

**DALY = YLL + YLD**
The DALY relies on an acceptance that the most appropriate measure of the effects of chronic illness is time, both time lost due to premature death and time spent disabled by disease. One DALY, therefore, is equal to one year of healthy life lost.

How much a medical condition affects a person is called the *disability weight* (DW). This is determined by disease or disability and does not vary with age. Tables have been created of thousands of diseases and disabilities, ranging from Alzheimer's disease to loss of finger, with the disability weight meant to indicate the level of disability that results from the specific condition.

Examples of disability weight| Condition | DW 2004 | DW 2010 |
| --- | --- | --- |
| Alzheimer's and other dementias | 0.666 | 0.666 |
| Blindness | 0.594 | 0.195 |
| Schizophrenia | 0.528 | 0.576 |
| AIDS, not on ART | 0.505 | 0.547 |
| Burns 20%–60% of body | 0.441 | 0.438 |
| Fractured femur | 0.372 | 0.308 |
| Moderate depression episode | 0.350 | 0.406 |
| Amputation of foot | 0.300 | 0.021–0.1674 |
| Deafness | 0.229 | 0.167–0.281 |
| Infertility | 0.180 | 0.026–0.056 |
| Amputation of finger | 0.102 | 0.030 |
| Lower back pain | 0.061 | 0.0322–0.0374 |

Examples of the disability weight are shown on the right. Some of these are "short term", and the long-term weights may be different.