Here are some notes from Stephen Cranney, “”Who Is Leaving the Church? Demographic Predictors of Ex-Latter-day Saint Status in the Pew Religious Landscape Survey,” BYU Studies Quarterly 58/1 (2019): 99-108:
Dr. Cranney, a researcher based in the Washington DC area who holds a dual Ph.D. in sociology and demographics from the University of Pennsylvania, points out that there is surprisingly little good data on the question. However, he finds the 2014 Pew Religious Landscape Survey helpful, and his article is based upon that. The Pew survey is, of course, restricted to the United States, and it has certain other limitations.
Here’s a striking assertion from the article:
[A]s of 2014 the Church appears to be treading water in terms of replacing those who leave with converts, meaning that any real growth comes from the natural growth of members of the Church having children. (101)
Please recall, once again, that this refers only to the United States, nowhere else. And, since the survey is more of a snapshot than a moving picture, it has relatively little to say about whether departures are accelerating (or remaining steady or decreasing) — though Dr. Cranney sees some clues in the data to suggest that the rate of departure from the Church was pretty much constant or stable from the inception of the survey in 2007 through its conclusion in 2014.
Dr. Cranney’s stark declaration should, however, give pause to those inclined to relax in the confidence that “all is well in Zion; yea, Zion prospereth, all is well,” and in the assumption that we’re growing rapidly. (I hope, in fact, that it will inspire some of us to further effort.)
By the same token, it provides no real support to those who believe (and, very commonly, hope) that the Church of Jesus Christ of Latter-day Saints is withering away and dying.
So Dr. Cranney concludes that, in terms of conversations/apostasies, the membership of the Church in the United States is — or, anyway, as of 2014, was — in a position of stasis.
As noted previously, however, this does not take into account the potential natural growth of children being born versus members dying, or the potential growth from population momentum, which could cause the Church to grow in the medium term due to its age structure, even in the absence of above-replacement fertility or conversions in the Church. (101)
Remember, though, that the average size of American Latter-day Saint families has decreased substantially over the past couple of generations, partially because the average age of first marriage has risen, so that that source of growth is not as strong as it once was.
To be continued.