DEMOGRAPHYconsiderable resistance in many places. Will they
continue to occur in other countries as the demo-
graphic transitions proceed around the world?
How serious will the resistance be in countries
more patriarchal than those of Europe? These
issues await future demographic research.
Immigration, emigration, ethnicity, and na-
tionalism. The difference between immigration
and emigration is, of course, net migration as a
component of population growth. In general, the
direct impact of net migration on growth has been
modest. Certainly emigration provided some out-
let for population growth in Europe during the
transition (Curtin 1989) and played a role in the
population of the Americas, Australia, and New
Zealand. Most of the effect of immigration to the
New World was indirect, however. It was the child-
ren of immigrants who peopled the continents
rather than the immigrants themselves. Contem-
porary interest in international migration has three
sources. First is an abiding concern for refugees
and displaced persons. Second is interest in a
highly mobile international labor force in the con-
struction industry. Third, and perhaps most im-
portant, is the migration of workers from less
developed countries to developed ones in order to
satisfy the demand for labor in a population in real
or incipient decline (Teitelbaum and Winter 1998).
In France, Germany, and England immigrants
who come and stay change the ethnic mix of the
population. In the United States, legal and illegal
immigration from Mexico has received consider-
able attention (Chiswick and Sullivan 1995). The
immigration of skilled Asians raises issues of an-
other kind. In all of these countries, the perma-
nent settlement of new immigrants arouses power-
ful nationalistic concerns. The situation provides
ample opportunity for the investigation of the
development of ethnicity and the place of endoga-
my in its maintenance. As with changes for child
rearing, these changes seem consequences of the
demographic transition. Below-replacement fer-
tility seems to generate the need for imported
workers and their consequent inclusion in the
society. If this speculation is true, how will coun-
tries more recently passing through the transition
react to this opportunity and challenge? This is
another arena for future demographic investigation.
Population aging, morbidity, and mortality.
Accompanying the reduction of fertility and of
population growth is the aging of the population
(Treas and Torrecilha 1995). Much of the devel-
oped world is experiencing this aging and its
concomitants. Countries that made a rapid demo-
graphic transition have especially dramatic imbal-
ances in their age distribution. Concerns about
retirement, health, and other programs for the
elderly generate interest in demographic research
in these areas. Will increasing life expectancy add
years to the working life so that retirement can
begin later? Or will the added years all be spent in
nursing homes? These questions are currently of
great policy interest and pose interesting and diffi-
cult problems for demographic research (Manton
and Singer 1994). Traditional demographic mod-
eling has assumed that frailty, the likelihood of
death, varies according to measurable traits such
as age, sex, race, education, wealth, and so on, but
are constant within joint values of these variables.
But what happens if frailty is a random variable? In
survival models, randomness in frailty is not help-
ful, or at least benign, as it is in so many other
statistical circumstances. Rather, it can have quite
dramatic effects (Vaupel and Yashin 1985). How
one models frailty appears to make a considerable
amount of difference in the answers one gets to
important policy questions surrounding popula-
tion aging.DEMOGRAPHY AS A PROFESSIONMost demographers in the United States are trained
in sociology. Many others have their highest de-
gree in economics, history, or public health. A few
are anthropologists, statisticians, or political scien-
tists. Graduate training of demographers in the
United States and in much of the rest of the world
now occurs primarily in centers. Demography cen-
ters are often quasi-departmental organizations
that serve the research and training needs of schol-
ars in several departments. In the United States
there are about twenty such centers, twelve of
which have National Institutes of Health grants.
The Ford Foundation has supported similar de-
mography centers at universities in the less devel-
oped parts of the world.Today, then, most new demographers, with-
out regard for their disciplinary leanings, are trained
at a relatively few universities. Most will work as
faculty or researchers within universities or at