Implementing Coale and Trussell's model of age-specific marital fertility rates and fitting the model to actual ASMFR.
CT(M=1, m=0)
fitCT(initialpar=c(1.0, 1.0), data, Method="Nelder-Mead", ...)
CT() returns model ASMFR for ages from 12 to 49. fitCT() returns the numeric vector of fitted parameters M and m, RMSE for those values, and the flag of convergence.
The parameter M of the CT model, the scale (peak height) parameter of fertility
The parameter m of the CT model, the strength of downward discordance from natural fertility with aging
Initial value for the parameters to be estimated. If not given, c(1.0, 1.0) is used.
Actual vector of ASMFR (which must be given for from age 12 to age 49 for each age) to be used to obtain the best-fit parameters of the CT's model.
The method to be used in optim() function. Default is "Nelder-Mead".
Other options to be passed to optim().
Minato Nakazawa minatonakazawa@gmail.com https://minato.sip21c.org/
Coale AJ, Trussell TJ (1978) Technical Note: Finding the Two Parameters That Specify a Model Schedule of Marital Fertility. Population Index, 44(2): 203-213.
Jfert
ASMFR <- c(0, 0, 0, Jfert$ASMFR2000[1:35]) # Jfert's ASMFR should be rearranged to 12:49
res <- fitCT(,ASMFR)
FLAG <- res[4]
while (FLAG>0) {
res <- fitCT(res[1:2], ASMFR)
FLAG <- res[4]
}
print(res)
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