I. Life Tables
A. Life Tables – a detailed description of the age-specific mortality, survival and expectation of life of a population
1. Life Table Example:
2. Life Tables answer these questions:
a. What is the life expectancy of a newborn?
b. How many years remain for the average individual?
c. Over what age groups do most deaths occur?
d. What is the trajectory of mortality at advanced ages?
e. What is the probability of an 18 year old dying in the next year? At 80?
f. What fraction of newborn in 2010 will live to the 22 century? nd
3. Life tables are important because they…
a. serve as barometer of current health in a population
b. identify trends in health and mortality
c. provides a baseline for prediction
a. Subscript x always denotes age (e.g. N , l , dx) x x
b. N 10number alive at age 10
c. 21= fraction alive at age 21
a. d85 deaths at age 85
A. Cohort Survival – l x
1. lx– the fraction of individuals in the initial birth cohort surviving to age x
a. l – radix, the number to which all numbers are related
b. In human demography, it’s normalized to 100,000; cannot divide n x
2. After you calculate l , xou need to put the solution in a full sentence
B. Period Survival – p – thexfraction of individual age x that survive to age x+1 C. Period Mortality – q – fraxtion of individuals age x that die in the interval x to x+1
1. complement of p ; p xq =x1 x
D. Period Deaths – d (frexuency of deaths) – fraction of individuals in the original cohort that die in the interval
x to x+1
E. Expectation of Life – e – average number of years remaining to an individual age x
1. Omega (ω) is the symbol for ‘oldest age’
F. Overview of Parameters
1. x is cohort survival; p isxperiod
2. pxand q axe complements
3. qxis a rate; d xs a density concept
4. All graphs
a. Red – survival to age 60
b. Green – ages 60-90: survivorship decreasing
c. Yellow – 90-100+ - mortality is high, low in dx because there is no one left to die G. Practice Table:
x N x lx px qx d x e x