Dr. Mike Walden, North Carolina Cooperative Extension economist in the College of Agriculture and Life Sciences at N.C. State University, responds:

"There are two big disadvantages, and analysts have to decide if those disadvantages outweigh the advantages of what the fiddling with the tax code is intended to achieve. One, of course, is obvious, that if you add more exemptions, deductions, credits to the tax code, you complicate it. You make the tax code more complex, more difficult to understand. And in some sense, I think you're also making it a little less trustworthy, in the sense that some person might think that guy or gal down the road is getting something in terms of a benefit I'm not getting. So I think we do have to watch that; we have to take that into account. The other thing is when you add these complications, usually what you do - what a policy maker does - is the complications are only added for certain kinds of taxpayers, usually defined by income. Well, what you have worry about is, How are you going to phase that out? Are you simply going to say, once you get to this level of income, boom, they're gone. Well, if you do that, that creates these break points in the tax code, and there have been lots of studies that have shown that people actually take these into account, change their behavior, maybe even decide not to take a better-paying job because it leads them away from being able to qualify for those tax goodies in the tax code. So those are two complications that we really have to keep in mind when we're trying to use the tax code for something other than simply raising revenue."