Years of Potential Life Lost
Premature mortality is measured by the Years of Potential Life Lost (YPLL) statistic, which is simply the sum of the years of life lost annually by persons who suffered early deaths.1 For the purpose of calculating YPLL, premature death is defined as death occurring before the age of 65. Thus, the population at risk of premature mortality is the group of Texas residents between the ages of 0 and 64. YPLL are calculated using death certificate data.
To calculate YPLL, the person's age at death is subtracted from 64.5. The result of this subtraction is the years of potential life lost by the decedent. The number of years of potential life lost by a person who died at age 60 is thus 4.5. Once YPLL is calculated for each decedent, individual YPLL values are summed to produce the total years of potential life lost by all Texas residents during the year.
YPLL = ∑ ( 64.5DEATHS - X decedent's age in years )
A further statistic, the YPLL rate, is the number of years of potential life lost before age 65 per 1,000 population ages 0-64.
YPLL Rate = ( YPLL / Population < 65 Years of Age ) * 1000
Alternative methods have been developed to estimate potential years of life lost. For example, 'Working Years of Life Lost' examines YPLL for individuals age 15 through 65 years. Life expectancies may also be used to define premature death (death before attaining the age of life expectancy at birth). The YPLL statistic may also be calculated for specific causes of death.
1. Premature Mortality in the United States: Public Health Issues in the Use of Years of Potential Life Lost. MMWR, 1986; 35: 2S, 1s-11s.
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Center for Health Statistics