I'm not sure I have a solution for quantifying. Even defining "empathetic acts" is something I struggle with. To me, the crux is whether someone puts themselves in the shoes of a less fortunate person. You can do this without helping, just like you can help without doing this.
Anecdotally, the homeless people I've spent time talking to seem to appreciate the conversation (or maybe being treated as a human being?) as much or more than the dollar or two I frequently give.
Utilitarianism might suggest donations as a decent proxy. Can't say I disagree, although I'd like to know how generous churches can be if they didn't receive a tax break.
It’s pretty hard to compare. Perhaps donations isn’t the right measure. What is more accurate?