I share PAL’s (or is it SF’s, or both’s) view of the problems with Stephen Prothero’s approach, but I can’t help calling attention to this review of the research, a hard copy of which crossed my desk just a few days ago. Heritage’s Patrick F. Fagan summarizes oodles of studies (a technical scholarly term) that point to the social utility of religion. What this has to do with the "truth" of (generic) religion is another question. I’d say only that there may be some inextirpable human needs that can’t adequately be addressed in any other way. If we recognize our neediness and finitude, we might also then recognize our creatureliness. But that’s the subject of (something more than) another post.
I’ll only note that Fagan’s policy-oriented conclusions are relatively modest. He urges polcy-makers to take this information into account as they deliberate, that the Census Bureau do more to collect data about religious practice, and that policy-makers "consider the effectiveness of faith-based approaches to social problems." I’d add this: if policy-makers recognize that a healthy civil society, centered around churches, addresses or avoids some social pathologies, with or without government assistance, they might be more inclined to get out of the way of that civil society and not assume that everything immediately requires a governmental answer. They might also inquire into what, if anything can be done, to restore a civil society that has been weakened, by public or private action.