A function to build lifetables and extract certain lifetable statistics from data.
Description
Accepts either single age or 5year abridged data. Accepts many optional arguments, such as differing methods for a(x) estimation, optional smoothing for M(x) or a(x) values, a changeable radix.
Usage
1 2 3 
Arguments
Nx 
numeric vector of population exposures by age. 
Dx 
numeric vector of death counts by age. 
Mx 
numeric vector of central death rates (assumed in the function to be the lifetable m(x)), calculated as deaths/exposure. 
ages 
optional, default = 
axmethod 
either 
sex 
either 
mxsmooth 
logical, default = 
axsmooth 
logical, default = 
radix 
The lifetable starting population at age 0, l(0). default = 1. Other common values are 1000 and 100000, although any value may be given. 
verbose 
logical, default = 
... 
further arguments passed to or from other methods 
Details
Either Nx
must be specified along with Dx
, *or* Mx
must be specified directly. If smoothing is used, it is better to specify both Nx
and Dx
, since the Nx
vector can be used as an offset in the MortalitySmooth
smoother.
Value
a list is invisibly returned

LT
Adata.frame
with 11 columns and as many rows as you have ages. The columns are "Age" (character age labels, i.e. with "+"), "ages" (numeric),"mx", "ax", "qx", "px", "lx", "dx", "Lx", "Tx", "ex"
. All the individual components of the lifetable can be called and are unrounded when individually called. Some additional values are also available: 
Age
character vector of ages. Denotes intervals in the case of an abridged table. 
ages
numeric vector of ages. Left side of interval. 
mx
the lifetable mx (may differ from a given Mx). 
ax
Chiang's ax, either given by the user or estimated inaxEstimate
. 
qx
typical lifetable qx. Death probability for interval x, x + n. 
lx
typical lifetable lx. Number of radix individuals entering age x. l(0) = the radix population. 
dx
typical lifetable dx. Whenradix = 1
(default), this is the probability density function of deaths. 
Lx
typical lifetable Lx. Lifetable exposure for the interval x,x+n. 
Tx
typical lifetable Tx. Total number of years remaining to be lived by the cohort entering age x. 
ex
typical lifetable ex. Life remaining life expectancy at age x. e(0) = life expectancy at birth. Two other estimates of e(0) are given below. 
Sx
probability of surviving from age x until age x + n (L_x+n/L_x). 
Widths
vector of age intervals (n).
Author(s)
Tim Riffe
References
The main reference for this function has been:
Preston et al (2001). Demography: Measuring and Modelling Population Processes. Blackwell Publishing
ax estimation also received input from:
Chiang C.L.(1968) Introduction to Stochastic Processes in Biostatistics. New York: Wiley.
Coale Anseley and Paul Demeny, with B Vaughan (1983). Regional Model Life Tables and Stable Populations. New York Academic Press.\ Keyfitz, Nathan (1966) A Life Table that Agrees with the Data. Journal of the American Statistical Association, 61 (314):30512. As described on page 4445 of: Schoen R. (1978) Calculating lifetables by estimating Chiang's a from observed rates. Demography 15: 62535.
function calls MortalitySmooth
: Carlo G Camarda (2009) MortalitySmooth: Smoothing Poisson counts with Psplines. (version 2.3 at the time of this writing) http://CRAN.Rproject.org/package=MortalitySmooth.
See Also
MortalitySmooth
, axEstimate
.
Examples
1 2 3 4 