Rates of Mortality Improvement on the Lexis Surface. Visualizing Age-, Period- and Cohort-Effects

Roland Rau, University of Rostock
Christina Bohk, University of Rostock
Magdalena Muszynska, Warsaw School of Economics
James W. Vaupel, Max Planck Institute for Demographic Research

We present surfaces of rates of mortality improvement. Based on two-dimensional plots of smoothed death rates, our "maps" depict the rate of mortality change over time. We argue that this approach provides an appealing exploratory tool to visually analyze mortality dynamics, in particular to detect age-, period-, and cohort-effects. International comparisons demonstrate that similar trajectories of life expectancy are not necessarily based on the same underlying mortality dynamics. For instance, minor life expectancy increases in the past were caused by cohort factors (e.g. Denmark) as well as by period factors (e.g. East Germany). An analysis by major causes of death for the United States shows that antagonistic cohort effects were instrumental for the slow life expectancy increase during the 1980s and the 1990s: If negative cohort effects of respiratory diseases and cancer had been absent, life expectancy would have increased much faster due to improvements in survival for heart diseases.