Thanks for the compliment, sbf.
I am not as well read as you presume. I just don't get much time to read books; I don't even watch tv these days.
I haven't seen the book, Sects and Stats, but from the table of contents it looks like the author focuses on "longitudinal data" (ie same data measured at different times) which I think is the most useful approach to understanding trends etc.
i sped read the Cragun and Lawson article. Some excellent observations there, using the figures Mormons, SDA and Watchtower publish.
I read some extracts of David Voas, some time ago. He made some excellent points about why religion generally is in decline, that I have to agree with, and backs it up with data. I agree decline is generational. From memory, he is the one who uses the Atlantic fishermen analogy, to describe JW's. I don't agree with that analogy, as I think the ordinary publishers are the "catch" not the fishermen.
Like you, I have also read somewhere that decline itself is not accepted by some "experts". That is bizarre. My explanation for such people is that those that are intellectually proud tend to be more vulnerable to "confirmation bias" than the average person. We were living in a time when one of the greatest events of human history is happening around us; the unshackling of society from the chains of religious superstition. There are very credible stats from USA, South Korea and Aust in recent times (some of the more religious of the advanced countries) each showing religion in decline at the rate of about 1% per year.