The analysis uses data from the General Social Survey and employs a set of scenarios based on differential age-specific fertility, migration, and denominational switching rates, as well as variation in the probability of religious transmission from parents to children.
The data allow the researchers to estimate conversion rates as well as migration and fertility by 11 religious categories. The base scenario of the population projections suggests a substantial increase in the proportion of Catholics, mainly due to immigration and fertility. Although the Protestant population will continue to increase in absolute terms, its share in the total population will decline.
The secular, "without religion” group remains small, even shrinking slightly by the middle of this century because of low fertility. As religious factors have a notable influence on demographic behavior (marriage and childbearing patterns), and thus on economic and social trends, this research is expected to be highly policy-relevant.
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