Chi Meson said:
(NB: I generally do not like these labels, but I like these "who's better" studies even less)
"Conservatives" tend to be more wealthy and tend to stick close to the traditional 10% tithe. wealthier conservatives are also looking for tax deductions. "Liberals" are more likely to forego a more lucrative career in order to devote their time to a cause. I tended to meet fewer conservative volunteers during my HFH stints. I'm not judging either "side" here, but there are more ways than cash by which to measure generosity.
It's also important to note that not all churches are "conservative." There are liberal churches that do a lot of charity work, and if one is lumping all religious charity into the "conservative" category, then that's not likely an accurate measure of who is donating to what.
Like you, I also put more weight on those who devote their time (time is money too, but not counted that way) to charities than those who throw money at them simply out of some obligation of "tithing." It also would depend on what the charity is. Some charity is more self-serving than truly charitable. For example, donating money to your church so the church can put on an addition or remodel or plant a new garden so your wedding photos will be more beautiful is recorded as charity, but is really a very self-serving, non-charitable donation. On the other hand, someone who is spending several hours a week offering free tutoring to poor children is being far more charitable even though that never appears in a tax record.
Also, if you give to someone in need, but don't do so through a registered charity, that's not going to be recorded in any tax record. Likewise, if you make an anonymous donation of goods that you just leave and don't get a receipt for, because you're not doing it for the tax deduction, that won't get recorded anywhere. Also, if you're not earning enough or donating enough to itemize deductions, and just take the standard deduction, there won't be a record of that either.
I also wonder how they define conservative and liberal? Are they basing it on party affiliation, assuming all Republicans are conservative and all Democrats are liberal? How is this connection made? There are a lot of moderates in both parties.
There are just too many reasons to not believe charity can be measured accurately in terms of dollars and cents to not trust such a comparison.