From George Barna’s newest study:

One of the biggest surprises to some people, however, is that a large majority of the nation’s unchurched population is drawn from the sector comprised of people who consider themselves to be Christian. In the United States, 83% of all adults label themselves “Christian.” The percentage is lower among the unchurched, but such self-identified Christians still outnumber those who do not embrace Christianity by a three-to-two margin (61% vs. 39%).

Later…

Other interesting insights into the self-identified Christians who have distanced themselves from a conventional church relate to their beliefs. Two-thirds (68%) hold a biblical view of God – that is, He is the all-knowing, all-powerful creator of the universe and He still rules that universe today. However, only one-third (35%) agree to any extent that the Bible is totally accurate in all the principles it teaches. Only one in seven (15%) claim that their religious faith is very important in their life. One out of five (22%) contends that the ultimate purpose of life is to love God with all their heart, mind, strength and soul. A mere one in seven (14%) claims to have a clear sense of the meaning and purpose of their life. And minorities of the group, ranging from one-quarter to one-third, support the notions of salvation by grace alone, Jesus Christ living a holy and sinless life on earth, and Satan existing today.

Demographically, the self-identified Christians among the unchurched stray from common assumptions. Within this group, women outnumber men; Boomers and their elders outnumber the young; downscale adults double the number of upscale unchurched; conservatives are more common than liberals; and whites outnumber minorities by nearly a three-to-one margin.

And…

Based on past studies of those who avoid Christian churches, one of the driving forces behind such behavior is the painful experiences endured within the local church context. In fact, one Barna study among unchurched adults shows that nearly four out of every ten non-churchgoing Americans (37%) said they avoid churches because of negative past experiences in churches or with church people.