R package MortCast

Estimation and Projection of Age-Specific Mortality Rates

Age-specific mortality rates are estimated and projected using the Kannisto, Lee-Carter and related methods as described in Sevcikova et al. (2016).

The main functions are:

• cokannisto: Extrapolates given mortality rates into higher ages using the Coherent Kannisto method. The original Kannisto method (with sex-independent extrapolation) is avalable in the function kannisto.
• lileecarter.estimate: Estimates the coherent Lee-Carter parameters for male and female mortality rates (Li and Lee 2005), i.e. sex-independent parameters a_x and k_t, and the coherent parameter b_x. In addition, it computes the ultimate b_x^u for rotation (Li et al. 2013). The underlying sex-independent estimation is implemented in the function leecarter.estimate.
• mortcast: Using estimated coherent Lee-Carter parameters and given future sex-specific life expectancies, it projects age-specific mortality rates, while (by default) rotating the b_x parameter as described in Li et al. (2013).

Functions contained in the package can be used for both, 5-year and 1-year age groups.

Other methods for forecasting mortality rates are available:

• pmd: pattern of mortality decline

• mlt: model life tables, using UN lookup tables. Note that the tables were updated in version 2.6-0 (October 2021). For previous version of the tables install 2.5-0, e.g. devtools::install_github("PPgp/[email protected]")

• logquad: log-quadratic mortality model

• mortcast.blend: combining two different methods

A life table can be constructed using the life.table function.

References

Li, N. and Lee, R. D. (2005). Coherent mortality forecasts for a group of populations: An extension of the Lee-Carter method. Demography, 42, 575-594.

Li, N., Lee, R. D. and Gerland, P. (2013). Extending the Lee-Carter method to model the rotation of age patterns of mortality decline for long-term projections. Demography, 50, 2037-2051.