Jonas Schöley , Interdisciplinary Centre on Population Dynamics
Demographers are uncertain about the shape of infant mortality over the first year of life. We present evidence that the age-trajectory of infant mortality displays both power-law and exponential behavior and is best described by a product of those functions: an "exponentially-truncated power law". We validate this model on US register data from which we derive infant life-tables with a daily age grouping stratified by sex and birth-cohort as well as medical and social strata. Across all populations under consideration the age-trajectory of mortality following birth is initially dominated by a power-law regime and over the course of infancy eventually approaches an exponential decline of less than a 1% reduction per additional day of age. The observed truncated power-law behavior may be the result of a shock-recovery or a mortality selection process.
Presented in Session 182. Age Patterns of Mortality