This is unbelievably perplexing to me. I know for a fact that at least once a week I run across an article about the decline of the faith and church membership in the U.S.
Does anyone really keep official, accurate and vetted numbers?
In short, no.
Vast differences in theology and accounting practices make it nearly impossible to really know how many members a church body has, whether active or occasional worshippers. That, in turn, makes side-by-side comparisons nearly impossible....Often a church's understanding of membership -- how it is started, how it is maintained and how it can be revoked -- influences counts........Roman Catholics, the largest U.S. church with a reported 69 million members, start counting baptized infants as members and often don't remove people until they die. Most membership surveys don't actually count who's in the pews on Sunday....That means it is possible, for example, to be born Catholic, married Methodist, die Lutheran and still be listed as a member of the 1 billion-member Roman Catholic Church. "The Catholic understanding of membership is that a person becomes a member upon baptism and remains a member for life," Gautier said. "Whether you show up at church or not is not what determines whether you're a member."
-- from the thread When It Comes to Church Membership Numbers, the Devil's in the DetailsDemographer Mary Gautier of the center said counting Catholics is really more art than science because parish rolls may not be up to date. Many Catholics drift from parish to parish without formally changing their membership and often don't report deaths in their families, the newspaper said.
-- from the thread Roman Catholics total 64 million in U.S. ["counting Catholics is really more art than science"]
Does anyone really keep official, accurate and vetted numbers?
No. I’ve done business with a number of churches over the years and getting a real number of attenders/members/congregants/ whatever is next to impossible. That’s not a bad thing.