There is an interesting recent book by two Catholic sociologists, Andrew Greeley and Michael Hout: The Truth about Conservative Christians (The University of Chicago Press, 2007). Much of it is not news to anyone who has been paying attention to the conservative Protestant subculture, though Greeley and Hout put a very useful emphasis on the diversity of this group and repeatedly moderate common stereotypes. What’s more interesting is two side claims they argue for and present evidence in support of.
One is their explanation of the decline of mainline and liberal denominations relative to conservative ones. They find that the primary explanation is demographic: conservative Christian women have had significantly more children for many decades. A secondary contribution is due to conservative Christians being able to retain the allegiance of their offspring better: there has been a decline in conversions from conservative to mainline denominations. Greeley and Hout reject a common proposed alternative explanation, that conservative Christianity has been gaining ground at the expense of mainline churches, and that this is because the mainline churches have become too liberal. It’s almost entirely a matter of demographics instead. This sounds plausible to me, and though I’m hardly the best person to judge, their evidence seems convincing.
The other side claim is even more relevant to secular people. They argue that statistically speaking, religious people are happier than the nonreligious, and that moreover, much of this effect is attributable to religious participation directly rather than indirect effects such as religion promoting community and social contacts and so forth. Indeed, they say “One of the more reliable generalizations in social science is that married and religious people are happier than people who have neither companionship nor faith” (p. 150), and that “religion per se is the causal factor in religious peoples’ greater happiness; it cannot be sloughed off as a consequence of correlated but substantively irrelevant factors . . . [A]dherence to the Bible principles in the Bible-oriented Conservative Protestant denominations also increases happiness” (p. 161).
Nonetheless, there seems to be enough out there to suggest that the connection between religion and happiness is at least plausible. It’s legitimate to say that that there is some social scientific evidence (indeed, a good deal beyond what Greeley and Hout do not list but only cite) that religion is good for most people.