Events and Meetings of Italian Statistical Society, Statistics and Demography: the Legacy of Corrado Gini

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Up the Gamma-Gompertz curve with gun and camera
Gustavo De Santis, Giambattista Salinari

Last modified: 2015-09-05


First, we propose a new procedure for the estimation of the parameters of the Gamma-Gompertz model (GGM) of adult and senior mortality, so as to circumvent the possible bias caused by period effects (e.g., a sudden reduction of mortality in certain years, due to, for instance, medical progress).

Then, we check two of the assumptions of the model: the constancy of the rate of ageing and the effect of the initial distribution of frailty on mortality deceleration. On data taken from the Human Mortality Database (female cohorts, from nine European countries, aged 75-99 years), the GGM failed both tests: ageing is not constant, and the deceleration of mortality is stronger than the model predicts. However, these deviations are relatively minor, especially at very old ages (90+).

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