Renewal and stability in populations structured by remaining years of life

Timothy L. M. Riffe, University of California, Berkeley

We transform data classified by chronological age into data classified by remaining years of life (thanatological age). A model for population renewal and the corresponding projection matrix are presented for populations structured by thanatological age. Period results are derived using all available data from the HMD and HFD. We compare the intrinsic growth rate, r, as derived from the classic Lotka equation versus that derived on the basis of thanatological age. We also compare some transient indicators between the two models. Empirical results suggest that r from the thanatological model tends to be less erratic than Lotka's r, and the trajectory to stability tends to be faster with less oscillation.