Arthur Brooks is a conservative researcher and the incoming president of the right-leaning American Enterprise Institute. He's also the author of a book on charitable giving, called Who Really Cares, that cites data showing that "households headed by conservatives give 30 percent more to charity than households headed by liberals." Every so often, his findings are trumpeted as proof that conservatives are more genuinely compassionate than liberals. And that's exactly what Nick Kristof did over the weekend. But the difference can be explained in one word, and it's not "compassion." It's "religion." A recent survey from Google similarly found that self-identified conservatives gave more to charity than did self-identified liberals. But they also found that "if donations to all religious organizations are excluded, liberals give slightly more to charity than conservatives do." Indeed, religious congregations are far and away the largest recipients of charitable gifts: In 2006, they made up 32.8 percent of all giving. But is that charity, at least charity as Kristof and Brooks are defining it? For instance: Utah is among the most Republican states in the nation, largely because of its heavily conservative Mormon population. Mormons tithe 10 percent a week to their church. But is that charitable giving? Or is it a membership fee? How much of it goes to anti-poverty programming? How much to church administration? Saying that conservatives give more to charity is another way of saying that conservatives are more religious. Which is not to say that interesting insights don't lurk amidst the data on charitable giving. But uncovering them would require thinner slicing of the numbers. For instance: What is charity? Endowing a named chair at Harvard is not, to me, an example of charitable giving. It's monument construction. But the money required to create the Marty Peretz Chair in Yiddish Literature at Harvard -- yes, that's real -- is folded into the same number as donations to fund soup kitchens. Does tithing count as charity? Do gifts to Princeton count as charity? To the Sierra Club? The New York Philharmonic? None of those causes bears a particular relation to whether a poor family can eat tomorrow. And what of income? As a class, the rich tilt right, and they also give more to charity, both because they have more, and because they benefit from the tax break. What happens when you control for income? The answer is that I don't know. But I'd like to. Brooks, however, isn't doing much to tell us. And using charity to score political points seems somehow against the spirit of the enterprise.