What does years of potential life lost measure?

• A. The number of years lost when death occurs before life expectancy
• B. The average lifespan of the population
• C. The number of years lived with disability
• D. The number of births during the year

Answer: (A)

Premature mortality burden is captured by years of potential life lost. This metric sums up the years of life that are not lived when a person dies before a chosen life expectancy. In practice, you take a reference life expectancy (a standard age, often 80, 75, or the population’s average life expectancy) and for each death occurring before that age, you count the difference between the reference age and the age at death. Add those differences across all early deaths to get the total years of potential life lost.

For example, if the reference life expectancy is 80 and someone dies at 50, that death accounts for 30 years of potential life lost. Deaths at older ages contribute fewer or zero years, which is why YPLL emphasizes younger deaths and the impact of premature mortality.

This differs from the other concepts: it’s not the average lifespan of a population, nor the total years lived with disability, nor any measure of births. It specifically focuses on years that could have been lived if death had occurred at or beyond the reference age.