Eco 572: Research methods in Demography
Current Status Life Tables
We will consider applications of current status life tables to nuptiality and breastfeeding.
Proportions Married
This is the example on page 90 of the textbook, showing proportions single by age for Turkish men in
1990. I start at age 15 rather than 0 because the proportion ever married is zero in the younger age
groups.
. clear
. input a n s
a
n
s
1. 15 3165061 3030203
2. 20 2581153 1853222
3. 25 2435765
629077
4. 30 2096899
180767
5. 35 1784121
77134
6. 40 1418784
43412
7. 45 1111113
26267
8. 50
980115
22527
9. end
Next I compute the proportion single in each age group, estimate the proportion single at age 50 (
s50
)
as the average of age groups 4549 and 5054, and compute SMAM. I add 15 because that's the age
at which I started, and multiply
s50
by 35 (which is 5015).
. gen p = s/n
. scalar s50 = (p[7]+p[8])/2
. quietly sum p in 1/7 // exclude 50+
. scalar smam = 15 + (5*r(sum)35*s50)/(1s50)
. display smam
25.003883
SMAM is 25 years and corresponds to the lighter area in the figure below scaled by
1s50
. (I create
two variables to split the proportion single in the fraction that will remain single by age 50 and the
rest, so I can show them in different colors.)
. gen p50=s50
. gen pr = pp50
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. graph bar p50 pr, stack over(a, gap(0) ) legend(off) ///
>
bar(2, color(51 102 153)) ///
>
title(Proportions Never Married by Age) ///
>
subtitle(Turkey Males 1990)
. graph export smamtk90.png, replace
(file smamtk90.png written in PNG format)
SMAM is often interpreted as the mean age at marriage conditional on marrying by age 50. This
interpretation applies to real cohorts only if we are willing to assume that nuptiality has been constant
over the last 35 years. However, the measure is a useful synthetic summary of period nuptiality even
without the assumption of stationarity. (In fact, the unscaled version has a direct interpretation as
time lived in the single state by Turkish men in 1990.)
Duration of Breastfeeding
In an earlier
handout on smoothing I showed that retrospective reports of duration of breastfeeding in
Bangladesh (as elsewhere), show very substantial heaping at multiples of 12 (and to a lesser extent 6)
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 Spring '06
 Rodriguez
 Demography, younger age, Breast milk, current status

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