TMatt passes along a story from LiveScience, in which the writer digs deep into current social science data to explore the changing religious landscape of America. What she finds is that the number of people who really believe in their religion is holding steady, but the half-hearted, casual believers are falling away. But the decline has not been uniform across churches:

On a denomination-by-denomination level, the picture gets more complex. While the overall number of strongly affiliated people has stayed stable, that’s because Evangelical Protestants have become more tied to their churches, while Catholics identify less strongly with their faith.

In the 1970s, there was only about a 5-percentage-point difference in how strongly Catholics and Evangelicals felt about their religion, Schwadel said. Today, it’s around 20 percentage points. About 56 percent of Evangelicals currently say they’re strongly affiliated with their religion, while only 35 percent of Catholics say the same.

What accounts for the discrepancy? In my experience, Evangelicalism typically involves a much more direct engagement, emotional and social, with one’s church community than does Catholicism. Relatedly, I’ve known plenty of people over the years who identify as Catholic, but who quit going to mass years earlier. You don’t really find Evangelicals who, having ceased to be churchgoers, still identify as Evangelical.