Churchgoing increases your charitable giving significantly - he's right. I'm too lazy to find the sources, but there have been several.
No, no -- he said CONSERVATIVE Christians give more than liberals. Did he mean liberals in general or liberal Christians? There are tens of millions of churchgoing Christians in this country who are not conservative. I'd like to see some evidence that they are less charitable than their conservative brethren.
Too, I think you have to be VERY careful when you talk about charitable donations. Where is the money going? If I write a check for $500.00 to James Dobson so he can further his political agenda, is that factored into what Jmcfst is talking about? Conservative Christians give millions to radio and tv preachers. It may be they do good work with the money. Billy Graham sure does. But it may also be they use the money to finance political crusades and keep themselves in the lap of luxury.