The Rising Share of Nonmarital Births Fertility Choice or Marriage Behavior? Response to Ermisch, Martin, and Wu*
Loading...
Date
2008-09
Authors
Stone, Joe A.
Stockard, Jean
Gray, Jo Anna
Journal Title
Journal ISSN
Volume Title
Publisher
Department of Economics, University of Oregon
Abstract
In a 2006 article in Demography, Jo Anna Gray, Jean Stockard and Joe Stone (GSSi)observe that
among black women and white women ages 20 to 39, birth rates increased sharply for unmarried women
over the period 1974 to 2000. But they also increased for married women, as well, and yet the total birth
rate for married and unmarried women combined was essentially unchanged; ii)conclude that's since the
total birth rate did not change, it seems obvious by inspection that the rises in unmarried and married birth
rates could not have come from a general rise in fertility among women 20-39; iii)argue that these
patterns are an example of a phenomenon called "Simpson's paradox", often illustrated by a joke, as told
at Harvard, that when a student transfers from Harvard to Yale, mean intelligence rises at both places.
Both means rise not because the average intelligence of the combined student bodies changed, but
because the composition of the student body changed at each school; iv) conclude that between 1974 and
2000, sharp increases in the proportion of women who were single, termed the single share, or Su,
changed the composition of the pools of married and unmarried women. The rising single share had a
selection effect on the pools of married and unmarried women akin to the hypothetical student transfer
from Harvard to Yale. Women with target fertility below the average for married women, but above the
average for unmarried women, became less likely to marry than previously, so that mean birth rates for
both groups rose over the period, and iv) using age/race-specific panel data, find parameter values
strikingly consistent with those predicted by their illustrative model, and a dominant role for the selection
effect of the single share in determining NFR on this. Recently Ermisch Martin and Wu (EMW) have
challenged the GSS findings and conclusions. In this response GSS respond to the EMW challenges, and
reaffirm the GSS results and conclusions.
Description
19 pages
Keywords
Non-marital births, Marriage, Non-marital fertility ratio, Illegitimacy ratio, Fertility