Years of life lost (YLL) measures health loss from early death, taking into account the age that death occurred. A death that occurs at a young age has a higher weighting than a death that occurs in old age. YLLs are calculated with reference to a standard life expectancy at each age (see Ways and Means: A report on methodology from the New Zealand Burden of Disease, Injury and Risk Study, 2006–16).
All YLL are valued equally, and life expectancy does not decline to zero at any age. However, to reflect society’s preference for present benefits, health losses that occur in the future have been discounted (3% discount rate) relative to those that occur in the past. The model life table West level 26 (female), selected for monitoring life expectancy in New Zealand, provides a life expectancy at birth of 82.5 years. The same standard is used for all population groups, regardless of gender and ethnicity, in order to enhance comparability. In addition, using different standard life tables on the basis of gender and ethnicity would imply different goals for different population groups, and so would be incompatible with the values of most New Zealanders (see Our Health, Our Future: Hauora Pakari, Koiora Roa).