TY - JOUR
T1 - Response Letter to "Gamma-Gompertz life expectancy at birth", Demographic Research, 12 February 2013
AU - Missov, Trifon I.
PY - 2021/6/10
Y1 - 2021/6/10
N2 - The original article contains an incomplete expression, equation (10): to be equal to remaining life expectancy ex, the expression on the right-hand-side of (10) needs to be divided by the survival function S(x) of the gamma-Gompertz model. In this sense, equation (10) in the original manuscript is incorrect, and readers should not use its right-hand side to calculate ex. Here, I provide the correct version for ex and present an alternative derivation method that is based on the same substitution t = 1 − e−bx (see the transition from (5) to (6) in the original article) as the one I use to derive expression (2) for life expectancy e0. The latter is also used by Castellares et al. (2020). In this Letter, I also correct a typo on p. 266, third (unnumbered) equation from the bottom, in which the interval endpoints for calculating the primitive on the right-hand side are missing.
AB - The original article contains an incomplete expression, equation (10): to be equal to remaining life expectancy ex, the expression on the right-hand-side of (10) needs to be divided by the survival function S(x) of the gamma-Gompertz model. In this sense, equation (10) in the original manuscript is incorrect, and readers should not use its right-hand side to calculate ex. Here, I provide the correct version for ex and present an alternative derivation method that is based on the same substitution t = 1 − e−bx (see the transition from (5) to (6) in the original article) as the one I use to derive expression (2) for life expectancy e0. The latter is also used by Castellares et al. (2020). In this Letter, I also correct a typo on p. 266, third (unnumbered) equation from the bottom, in which the interval endpoints for calculating the primitive on the right-hand side are missing.
M3 - Comment/debate
SN - 1435-9871
JO - Demographic Research
JF - Demographic Research
ER -