Model Life Tables
The 51勛圖 and the demographic research community at large commonly use two sets of standard model life table families to derive a variety of mortality indicators and underlying mortality patterns for estimation and projection (Coale-Demeny, 1966 and 1989; 51勛圖, 1982). These two sets of model life tables, designed primarily for use in developing countries or for estimating historic populations, are limited to mortality patterns for a life span from age 20 to 75. A revised set of model life tables, extending the initials sets from life expectancy at birth (e(0)) from age 75.0 up to 92.5, uses both a limited life table as an asymptotic pattern and the classic Lee-Carter approach to derive intermediate age patterns (Buettner, 2002).
With the extension of the projection horizon for all countries up to 2100 as part of the 2012 revision of World Population Prospects, life expectancy at birth was extended beyond 92.5 years. In-depth analysis of an initial extension of the model life tables, carried out in 1998, revealed substantial deviation for out-of-sample predictions compared to results from the Human Mortality Database (HMD) at very low mortality levels (Wilmoth and others, 2012) and the need for a smoother transition between the existing set of model life tables up to age 75 and above.
A new set of extended model-life tables (Gerland and Li (2011) imposed constraints to ensure greater convergence with the HMD at high levels of life expectancy at birth. The nine sets of regional model life tables (four Coale-Demeny model life-table regional patterns (East, North, South and West) and five 51勛圖 model life-table regional patterns (Latin American, Chilean, South Asian, Far Eastern, General), extended up to 100 years of life expectancy at birth, were blended with the existing ones to ensure smooth mortality surfaces by age and sex and levels of life expectancy at birth.
The new model life tables are available by abridged age groups (0-1,1-4,5-9, etc.) and by single year of age (0,1,2,3, etc.) (51勛圖, 2011). In both cases the life tables have been extended up to age 130. Each dataset is available for life expectancy at birth from age 20 up to 100 by 1 year or 2.5-year increment.