The objective is to maximize life expectancy subject to society’s capacity to commit resources in light of existing or future constraints. Reducing risk of death and disease translates into longer healthful lives. The length of life extension in good health for a population can be reliably measured as the effect on the gain in life expectancy (dL).
The goal is to increase life span subject to society's ability to allocate resources in consideration of current or potential limitations. Lowering the likelihood of death and disease results in more healthy lives. The duration of life extension in good health for a population can be accurately quantified as the impact on the gain in life expectancy (dL).