80 Michael Hout
to equalize or even reverse the relative sizes of the religions. It looks like the process
that lies beneath the so-called decline of the mainline Protestant denominations in the
United States (Hout et al. 2001). Imagine if their higher fertility made Catholics the
dominant religion in Northern Ireland or Muslims the dominant religion in Israel (see
Kennedy 1973 for a discussion of the Northern Irish case). Suddenly demography looks
relevant for religion after all.
The power of demographic analysis comes from this ability to understand how soci-
ety changes even when no member of society has changed. That makes it a quintessen-
tially sociological form of explanation – at once powerful, complete, and free of refer-
ence to individual change. Arthur Stinchcombe considered this style of demographic
explanation in his classic text,Constructing Social Theories(1968), but too few sociolo-
gists practice it.
Research has shown that demography plays a role in real life; it is far more than
thought experiments. As religious researchers accumulate ever-longer time series and
ever-more-sophisticated databases, the potential for evaluating demographic explana-
tions of religious beliefs and practices will grow. And future sociologists of religion will
see a demography chapter as a natural part of their handbook.
BASICS: POPULATION, EVENT, AND EXPOSURE
The most basic notion in demography is the “population,” the pool of people being
studied. The demographer’s concept of population includes the everyday meaning,
that is, the people inside some geographic or political boundary. But in principle, a
population is any aggregation worth studying, for example, Protestant clergy, people
raised Jewish, native-born children of immigrants. Make population as broad or narrow
as your theory warrants. Populations do not even necessarily have to be composed of
living beings, for example, Catholic parishes, utopian communes, and faith-based social
welfare agencies might be populations (e.g., Carroll and Hannan 2000). The idea is so
basic that it probably seems trite, but it is also so basic that it is completely indispensable.
The twin ideas of “event” and “exposure” are also essential ideas to demographers.
They are less intuitive. A demographer’s understanding of what counts as an event is
a bit narrower than the everyday usage. Demographers are mostly interested in events
that have consequences for the size of the population; births, deaths, and moves into
or out of a population can be thought of as the main events. Marriages, divorces, en-
rollment in school, retirements, and other important transitions that are closely tied
to the life cycle have gotten attention from demographers over the years. For religious
researchers the list would be expanded to include baptisms, confessions of faith, and
annulments for individuals as well as foundings, mergers, and schisms within popula-
tions of religious organizations (e.g., denominations, congregations, or monasteries).
In principle, though, any event might be studied using demographic methods.
“Exposure” is the opportunity or risk of experiencing an event. Demographers char-
acteristically use the phrase “exposure to risk” even when the event in question is more
of an opportunity than a risk for what amounts to historical reasons: The ideas arose
first in the study of mortality. Exposure is important because events cannot happen to
people who are not exposed to the risk (or opportunity) of the event occurring. For the
demographer, exposure is important because some women are too young to have chil-
dren; some are too old; married people cannot get married again without first getting