BACKGROUND
The Own-Children Method is a widely used procedure for estimating levels, trends, and differentials in age-specific and total fertility from the age distribution.

OBJECTIVE
This article demonstrates that the procedure used in most applications of the Own-Children Method produces systematically biased estimates of the age pattern of fertility and describes a new estimator that avoids this bias.

METHODS
The Own-Children Method incorporates an adjustment for the proportion of children by age who are not living with their mothers. Because these children include orphans and because women’s mortality accelerates with age, this adjustment overestimates births to young women and underestimates births to older women relative to the number of women in the denominators of the fertility rates. By explicitly estimating the prevalence of maternal orphanhood by age, age-specific fertility can instead be calculated using a formula that avoids this bias.

RESULTS
The bias in the estimated age pattern of fertility is trivial for rates calculated from children born in the few years before an inquiry, but increases with the age of the children and with the population’s mortality. Its overall impact is to shift the fertility distribution toward younger ages at childbearing. Because the errors for women of different ages more or less cancel each other out, the bias in estimates of total fertility is smaller.



中文翻译：

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生育率估算的亲子方法：细节决定成败（作者：Ian Timaeu​​s）

背景
亲子生育法是一种广泛使用的方法，用于根据年龄分布估计特定年龄生育率和总生育率的水平、趋势和差异。

目标
本文展示了在大多数亲子方法应用中使用的程序对生育年龄模式产生了系统性有偏差的估计，并描述了一种避免这种偏差的新估计量。

方法
自己的孩子方法结合了按年龄不与母亲同住的儿童比例的调整。由于这些儿童包括孤儿，而且妇女的死亡率随着年龄的增长而加速，因此相对于生育率分母中的妇女人数，这种调整高估了年轻妇女的生育率，而低估了老年妇女的生育率。通过按年龄明确估计产妇孤儿的流行率，可以使用避免这种偏差的公式来计算特定年龄的生育率。

结果
对于根据调查前几年出生的儿童计算的比率，估计生育年龄模式的偏差是微不足道的，但随着儿童年龄和人口死亡率的增加而增加。其总体影响是将生育率分布向更年轻的生育年龄转移。由于不同年龄女性的误差或多或少会相互抵消，因此总生育率估计值的偏差较小。