Americans change religious affiliation early and often. In total, about half of American adults have changed religious affiliation at least once during their lives. Most people who change their religion leave their childhood faith before age 24, and many of those who change religion do so more than once. These are among the key findings of a new survey conducted by the Pew Research Center’s Forum on Religion & Public Life. The survey documents the fluidity of religious affiliation in the U.S. and describes in detail the patterns and reasons for change.

The reasons people give for changing their religion – or leaving religion altogether – differ widely depending on the origin and destination of the convert. The group that has grown the most in recent years due to religious change is the unaffiliated population. Two-thirds of former Catholics who have become unaffiliated and half of former Protestants who have become unaffiliated say they left their childhood faith because they stopped believing in its teachings, and roughly four-in-ten say they became unaffiliated because they do not believe in God or the teachings of most religions.1 Additionally, many people who left a religion to become unaffiliated say they did so in part because they think of religious people as hypocritical or judgmental, because religious organizations focus too much on rules or because religious leaders are too focused on power and money. Far fewer say they became unaffiliated because they believe that modern science proves that religion is just superstition.

Catholicism has suffered the greatest net loss in the process of religious change. Many people who leave the Catholic Church do so for religious reasons; two-thirds of former Catholics who have become unaffiliated say they left the Catholic faith because they stopped believing in its teachings, as do half of former Catholics who are now Protestant. Fewer than three-in-ten former Catholics, however, say the clergy sexual abuse scandal factored into their decision to leave Catholicism.

In contrast with other groups, those who switch from one Protestant denominational family to another (e.g., were raised Baptist and are now Methodist) tend to be more likely to do so in response to changed circumstances in their lives. Nearly four-in-ten people who have changed religious affiliation within Protestantism say they left their childhood faith, in part, because they relocated to a new community, and nearly as many say they left their former faith because they married someone from a different religious background.

The new survey is a follow-up to the “U.S. Religious Landscape Survey,” conducted by the Pew Forum in 2007 and released in 2008, and is based on recontact interviews with members of the largest segments of the population that have changed religious affiliation. This includes more than 300 interviews each with former Catholics who are now unaffiliated, former Catholics who are now Protestant, former Protestants who are now unaffiliated and those raised unaffiliated who now belong to a religious faith. The survey also includes nearly 300 interviews with people who have gone from one denominational family to another within Protestantism and nearly 1,000 interviews with people who still belong to the group in which they were raised. In total, the new survey allows for in-depth analysis of about eight-in-ten of those who now have a different religious affiliation than the one in which they were raised.2

One of the most striking findings from the 2007 Landscape Survey was the large number of people who have left their childhood faith. The 2007 survey found that more than one-in-four American adults (28%) have changed their religious affiliation from that in which they were raised. This number includes people who have changed from one major religious tradition to another, for instance, from Protestantism to Catholicism or from Judaism to no religion. If change within religious traditions is included (e.g., from one Protestant denominational family to another), the survey found that roughly 44% of Americans now profess a religious affiliation different from that in which they were raised.

The results of the new survey offer a fuller picture of the churn within American religion and suggest that previous estimates actually may have understated the amount of religious change taking place in the U.S. First, among the 56% of the population that currently belongs to the same religion as the one in which they were raised, one-in-six (16%) say there was a time in their life when they had a different faith than they have now. Combined with the 44% of the public that currently espouses a religion different than their childhood faith, this means that roughly half of the U.S. adult population has changed religion at some point in their life.3 Moreover, it is also clear that many people have changed religious affiliation more than once. For example, roughly two-thirds of those who were raised Catholic or Protestant but now say they are not affiliated with any particular religion have changed faiths at least twice in their life, including those who have changed within the unaffiliated tradition (e.g., from atheist to agnostic). The same is true for roughly half of former Catholics who have become Protestant, people who have changed denominational families within Protestantism and people who have become affiliated with a religion after having been raised unaffiliated.

The survey finds that religious change begins early in life. Most of those who decided to leave their childhood faith say they did so before reaching age 24, and a large majority say they joined their current religion before reaching age 36. Very few report changing religions after reaching age 50. Religious commitment as a child and teenager may be related to the propensity to change religion. The survey finds key differences, for example, in the levels of teenage (ages 13-18) religious commitment between former Catholics who have become unaffiliated and those who have kept their childhood faith. Former Catholics who are now unaffiliated are much less likely than lifelong Catholics to have attended Mass regularly or to have had very strong faith as teenagers. Similarly, currently unaffiliated former Catholics are somewhat less likely than those who have remained Catholic to say they had very strong faith as children. On other measures, however, such as participation in youth groups or religious education classes, there are few differences in childhood religious commitment between those who have remained Catholic and those who have left the Catholic Church to become unaffiliated.

The survey also finds major differences in childhood religious practices and commitment between lifelong Protestants and those who have left Protestantism to become unaffiliated. Former Protestants who are now unaffiliated are less likely to have regularly attended worship services as a child and even less likely to have attended regularly as a teenager. They also are much less likely to report having attended Sunday school or having had very strong religious faith as a child or a teenager.

The faith of most people who have changed religions was on the wane in the year or two prior to leaving their childhood religion, with few saying they had very strong faith during this time. Among those who left Catholicism and are now Protestant, for example, fewer than one-in-four (23%) say their faith was very strong just prior to leaving the Catholic Church. Among those who switched from one Protestant denominational family to another, only 30% say their faith was very strong just prior to leaving their childhood religion. The numbers are even lower among those who have become unaffiliated, with only 10% of former Catholics and 11% of former Protestants saying they had very strong faith just before leaving their former religion. This is consistent with another of the survey’s key findings – that among both former Protestants and former Catholics who are now unaffiliated, more than seven-in-ten say they just gradually drifted away from their childhood religion.

Reasons for Changing Religions

The new survey includes two types of questions that probe the reasons people change religious affiliation. Respondents received a set of closed-ended (yes-or-no) questions that asked whether or not various reasons factored into their decision to leave their former religion and join their current one. Respondents also were asked open-ended questions that gave them the opportunity to explain in their own words the main reason they left their former religion and joined their current one.

In response to the yes-or-no questions, people give a diverse array of reasons for changing their religion. For instance, the most common reason for leaving Catholicism cited by former Catholics who have become Protestant is that their spiritual needs were not being met (71%). A similar number of former Catholics who have become Protestant say they left their former religion because they found another faith they liked more; nearly six-in-ten of those who changed denominational families within Protestantism also say this. Not surprisingly, many who have changed religion say they left their former religion because they stopped believing in its teachings. For example, nearly two-thirds of former Catholics who have become unaffiliated say they left the Catholic Church because they stopped believing in its teachings. This sentiment is also expressed by half of former Catholics who have become Protestant as well as half of former Protestants who have become unaffiliated.

When asked in the open-ended question to explain in their own words the main reason they are no longer part of their former religion, roughly half of former Catholics give an explanation related to religious and moral beliefs. The same is true of roughly four-in-ten former Protestants who have become unaffiliated.

By contrast, those who have changed denominational families within Protestantism are much less likely to cite beliefs as the main reason for leaving their former religious group; the same is true for those who have become affiliated with a religion after having been raised unaffiliated. Instead, those changing within Protestantism tend to cite likes and dislikes about religious institutions, practices and people (36%) as the main reason for leaving their former faith. Life cycle changes also figure prominently for this group, with three-in-ten mentioning marriage, family or other changes in their life as reasons for their departure from their childhood faith. Many (26%) of those who have become affiliated after having been raised unaffiliated cite reasons related to personal spirituality as an explanation for why they first became involved with a religion.

These and other topics are explored in greater detail in the remainder of this report, which focuses on the largest segments of the U.S. population that have changed religious affiliation. The first section looks at those who have entered or departed the ranks of the unaffiliated. The second section takes a detailed look at those who have left Catholicism. And the third section examines the reasons why people change affiliation within Protestantism.

Read the complete report here.