(RNS) — More than three-quarters of U.S. members of the Church of Jesus Christ of Latter-day Saints describe themselves as attending church at least once a week, according to a recent study from the Pew Research Center.   Another new study, this one from B.H. Roberts Foundation, similarly found that 71% of Mormons who live in LDS areas of the U.S. attend church weekly, and 65% do who live outside those geographic strongholds.  Heck, my own research in the Next Mormons Survey showed very high weekly LDS attendance as well, measuring at 74% in 2016. But what if we’re all wrong? Or at least, what if the self-reported data all these studies have relied upon presents an incomplete picture? Scholars who study religion have long understood that the number of people who say they’re in church on a given Sunday is higher than the number who are actually there. For example, one famous 1990s study found that fully half of the Christians who called themselves weekly attenders were likely not. That study relied on churches’ …