Changes in American Religious Identification

Gallup reports that the United States remains an overwhelmingly Christian nation, although the proportion of Americans identifying with some denomination of Christianity has been declining for decades. Check the link for the whole report, which includes time-series graphs going back to 1948. Here's the summary and conclusion:

The United States remains a dominantly Christian nation. More than three-quarters of all Americans identify as Christian. And the vast majority of those who identify with any religion say they are Christian in some form or another.

Yet, the percentage of Americans who in theory could celebrate Easter this weekend as part of their religion is down significantly from where it was 50 or 60 years ago.

There are many theoretical explanations for the increase in those with no religious identity at the expense of those identifying with a Christian religion. Two social scientists at the National Opinion Research Corporation, Tom W. Smith and Seokho Kim, contemplating similar data from the General Social Survey in 2004, concluded: "In sum, an array of social forces from cohort turnover, to immigration, to reduced retention rates, indicate that the Protestant share of the population will continue to shrink and they will soon lose their majority position in American society."

The share of the population held by any religious group is based on a complex set of factors relating to internal reproduction (births), in-migration (from converts and from people moving into the country who have a particular religious identity), and out-migration (people who leave the religion and people with a particular religious identity who leave the country). In-migration from other countries in recent years may have helped boost the percentage of non-Christians in the population. In-migration from Catholic Mexico and Catholic Central American countries has also, at the same time, helped keep the percentage of Catholics as high as it is. The big shift has apparently been the out-migration of those whose parents may have identified with a specific Christian religion, but who upon growing up have become more likely to tell a survey interviewer that they have no specific religious identity.

Gallup (and other survey researchers) measure religious identity by asking Americans to name their religion. It is possible that Americans who previously would have identified themselves with the religion of their upbringing now feel freer to tell a survey interviewer that they have no religious identity.

It is important to note that basic religious identification says little about the relevance of that identify to the person's life. Identifying with a religion doesn't indicate how actively the individual practices the religion. It doesn't indicate whether the person rigorously adheres to that religion's beliefs. It simply states that the person has some connection to and some identity with a specific type of religion. Data from measures of religious intensity or commitment are needed to flesh out the portrait of the ways in which Americans' religiosity may have changed over the years.

Gallup survey data on religious identification extend back only to 1948, about a quarter of the life of the country. Obviously, this evidence speaks only to the recent history of religious identity in the United States. There is no real scientific way of putting recent survey history of religious identity into a longer time frame going back much before World War II. (Some scholars argue that, in fact, Americans were not very religious by some measures at the time of the Revolution in Colonial America.) It is thus important to keep in mind that the trends reviewed in this analysis are only part of the portrait of the ebb and flow of religion in the United States since the nation's founding well over two centuries ago.