This document describes how to construct a life table by calculating various demographic rates and statistics from population and mortality data. It involves calculating: age-specific death rates; total deaths by age group based on death rates and population; life table mortality rates from death rates and age intervals; survival rates from mortality rates; number of survivors by age from survival rates; person-years lived from number of survivors; and life expectancy at each age based on person-years lived. The life table provides information on mortality patterns and expected remaining lifespan by age.
3. Notes:
Calculation of total deaths (D):
i) 0-1 age group= (IMR*total births)/100000
ii) 1-85+ age-groups= ASDR*P/1000
Calculation of age-interval:
count the number of each single
age, included in the group
Calculation of nMx from ASDR=
Total deaths d/ (Age-interval n*
Population P)
Calcualtion of nqx fromnMx =
i) 0-1 age group= (D/P)
ii) 1-84 age-groups=
(2*n*nMx)/(2+(n*nMx)), n=age
interval, nMx= life table death rates
Note: there are multiple procedures to convert
nMx to nqx, we here are following the formula
of Acturial Method, which assumes, Population
and Death are linearly distributed within a
particular age-group.
iii) 85+=
1 (since all of them will die
eventually)
Calculation of ndx
ndx = nqx *nlx
4. Calculation of lx
i) At age 0 (radix of life table)= 100000
ii) 1-85+ age-groups= lx+n= lx-ndx
Calculation of nLx
i) 0-1 age group= 0.3*l0 + 0.7*l1
ii) 1-84 age-groups= (n * (lx+lx+n))/2
iii) 85+= ndx /nMx
Calculation of nTx
i) T85+= T85/l85
ii) Rest of the age-group Tx+n + nLx
where,Tx+n is from the next group and
nLx is from the earlier age group