+ Weibull and Gompertz Models

Question 1

Initial mortality: Gompertz vs Weibull

Answer 1

• Both models feature an initial mortality rate
• Minimum mortality rate suffered by young adults prior to the onset of physiological decline

Question 2

Key difference between Weibull and Gompertz parameters:

Answer 2

• Gompertz: aging-related mortality increases exponentially as a multiple of initial mortality
• Weibull: aging-related component of mortality is a power function of age that is added to initial mortality rate (allows for the initial mortality rate to be 0 in contrast to Gompertz where it must be positive) -> implying different, independent and additive causes of death over time; also incorporates death due to catastrophic intrinsic causes whose probability increases with age