IAI Actuarial Core Principles · Risk Modelling and Survival Analysis · Mortality projection
A Cairns-Blake-Dowd (CBD) model is fitted with logit q(x,t) = k1(t) + k2(t)(x - xbar). Which statement is correct?
The CBD model is aimed at older ages. Its time-varying k1 sets the overall level of logit mortality, while k2 sets the slope across ages. Cohort effects appear only in extended versions, and there are no age-specific a(x) or b(x) parameters.
- AIt is designed for older ages, with k1 as the overall level and k2 as the slope of the logit mortality curve across agesCorrect
- BIt includes a cohort effect in its basic two-factor form
- CThe parameters k1 and k2 are constant over time
- DIt models mortality at all ages from birth with age-specific parameters a(x) and b(x)
- k2 is the average mortality at the mean age xbar
Explanation
The basic CBD model targets higher ages and has two time-varying factors: k1 shifts the level of logit q and k2 changes its slope with age. Cohort terms exist only in extensions. Unlike Lee-Carter, it has no age-specific a(x) or b(x).
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