Outside surveys have also tracked the decline. New findings released this year show the Southern Baptist trajectory more closely resembles the downward trend among the United Methodist Church (UMC), the nation’s largest mainline Protestant body, than fellow evangelicals in non-denominational traditions.
According to the General Social Survey (GSS), nearly the same percentage of Americans identified with the SBC as the UMC in the 1980s, then the two denominations’ trends began to separate, and both experienced a slow, steady decline from the mid-’90s on.
While close to 1 in 10 Americans identified as Southern Baptist in 1987, that number has been cut in half to 1 in 20 (4.8%) in 2018. Data from the Cooperative Congressional Election Study (CCES) reinforces this point as well, with 5.4 percent of the sample identifying as SBC.
There are four major ways for a religious denomination to change in size over a longer period of time: They add members through conversions, they keep those born into the faith as they grow up, they shed members through people defecting to other religious traditions, or members die and are not replaced by young adults.
Every religious group experiences these losses to some extent—like a bucket that has sprung a few leaks. While some of the water will inevitably trickle out, it’s possible to put more water back in the bucket from other sources. If the amount of water that leaks out is greater than the amount of water that is replaced, then a decline will occur in overall members. The Southern Baptist Convention has a bucket that is aging and springing more leaks every year.
As evangelicals, Southern Baptists put particular emphasis on conversion as a potential source of membership growth and celebrated around a quarter of a million baptisms last year, according to ACP figures. However, nearly all Southern Baptists have been part of the denomination for a while.
CCES, which tracked the same group of 9,500 respondents in 2010, 2012, and 2014, found few newcomers to the SBC during that time. Of the 476 Southern Baptists in the sample in 2014, close to all of them (97.9%) had also identified as Baptists in 2010. Of those who converted to the SBC, two had been Catholics, two were from other faiths, and six had been religious “nones.” These numbers are too small to make claims about converts from any specific group, but the overall impression is clear: Southern Baptists are not seeing significant growth through conversion.
The necessary follow-up question, then is: Are a lot of Southern Baptists leaving the faith? CCES data also showed that 91.8 percent of people who started out as SBC in 2010 were still SBC four years later. Of the 37 people in the sample who left the SBC between 2010 and 2014—not a significant enough portion to extrapolate—31 of them either became a non-denominational Protestant or some other type of Protestant Christian. Just two became “nones.” Obviously, any defection is disappointing for those who want to see the SBC grow, but based on this sample, of the members who do leave, they often don’t stray too far.