(AP Photo/Seth Wenig)

The Supplemental Nutrition Assistance Program, or SNAP, is one of America’s most important welfare programs. It is also frequently misunderstood by both lawmakers and citizens.

Among the stories you may have heard about SNAP: It’s rife with fraud; it’s abused by immigrants; it’s typically used to buy junk food. Many economists who have studied the program say there’s little evidence these stories are true.

In fact, many economists believe that SNAP is a singularly effective program. One of them is Craig Gundersen, a professor of agricultural and consumer economics at the University of Illinois at Urbana-Champaign who has spent the last 20 years researching it. Gundersen's views are not universal: The safety net is complex, after all. But his work -- which has been funded by the Department of the Agriculture, as well as numerous charitable foundations and anti-poverty groups -- includes nearly 200 published papers and a book on the economics of the program, titled "SNAP Matters." Gundersen has also traveled the country, explaining SNAP to state legislatures, Congressional committees, agricultural groups, anti-hunger advocates, and fellow academics.

Recently, the Post met up with Gundersen to ask him to debunk some of the most common questions we get about SNAP. This is a lightly edited transcript of that conversation.

Craig Gundersen (University of Illinois)

First things first: Who is the average SNAP participant, if you could describe that person?

The average SNAP participant would be a child. The highest proportion of SNAP participants are children. Of those who aren’t -- and I think this is one of the things worth emphasizing about SNAP -- is that of those who aren’t children or on disability or retired or something like that, the majority do work. But more than half of SNAP participants are children.

That is a claim we tend to hear a lot -- that SNAP discourages work, or that adults on SNAP aren’t working. You’re saying that’s not the case?

This is one of those claims that’s really frustrating. Well -- everything is frustrating, so I’ll stop saying that. But there are some welfare programs that discourage work. SNAP is not one of them.

Medicaid discourages work: If you earn one dollar more than the cut-off, you lose all your benefits. So if you’re right at the cut-off point, maybe you say ‘I’m not going to work more hours,’ or ‘I’m not going to take a higher-paying job’ or whatever.

No steak, no seafood, no strip clubs: There's a logical gap in the recent laws that bash the poor who receive government welfare and food stamps. (Tom LeGro/The Washington Post)

Or the old Aid To Families with Dependent Children program -- I don’t think there’s any doubt that it discouraged people to work. But that wasn’t because the people getting the benefits are lazy -- well, I’m sure some of them were -- but generally, the disincentive was the fact that there was a huge tax rate on AFDC benefits. [Note: Under AFDC, benefits increased very slightly with higher incomes, to encourage recipients to work; but taxes on those benefits rose far faster.]

What makes SNAP perfect is that the tax on each additional dollar of income is 24 cents. There’s not a disincentive to work, except insofar as all taxes are disincentives to work. And I don’t think that 24 percent is a high tax rate in this context.

There’s also no cliff effect with respect to SNAP, because as your income increases, your benefits gradually go down. There’s always a lot of misinformation around this. There was even a recent Congressional report [note: published by the House Committee on Agriculture in December] that misinterpreted it. SNAP combined with other programs can discourage work -- but that’s the fault of the other programs, such as Medicaid. Not SNAP.

What about this one: We hear sometimes that SNAP participants use lots of money to buy junk food -- soda specifically. What do we know about what people buy with SNAP?

Well, that’s very complicated. The main thing we’re interested in is how SNAP participants compare to eligible non-participants. The answer is that they’re not much different.

But even so -- the Food and Nutrition Service released a study on this in November, and it was well-done, given the questions that FNS was posing. But the questions they were posing weren’t useful. Basically, the study asked ‘how do people spend their SNAP benefits?’ But SNAP participants also use additional cash to purchase food, and it didn’t consider that. So it doesn’t tell us anything about what people are consuming.

It could be that SNAP participants actually spend a lot less on junk food than eligible non-participants, but they’re using their SNAP benefits for the soda, and cash for everything else. Or perhaps it has something to do with the fact that SNAP benefits tend to be spent at the start of the month. Maybe people want to make one stop with their SNAP benefits at the start of the month, so they buy things that are nonperishable -- say six two-liter bottles of Coke. Then for the rest of the month they spend cash on milk and fruits and vegetables. You’re not getting that perspective.

The other problem with these comparison studies is that they have huge selection effects. SNAP benefits are not randomly distributed. So unless you control for that, you’re going to get odd answers. Overall that study should not be informing our policy. I don’t even know why FNS commissioned it.

This one is related: I once got a very vehement email from a reader who was convinced that SNAP benefits could be spent at fast food restaurants. Is that the case?

No. I have no idea what he could have been referring to. I mean, there’s a very small waiver program that allows SNAP benefits to be used at approved restaurants in some places, if you’re disabled or homeless. But unless that guy is in one of those areas, it’s just not happening.

Can SNAP participants sell their benefits for cash? And do we have any idea how much that happens?

Selling EBT cards is an urban myth. That is precisely the reason we have EBT cards. Back previously, when you had food stamp coupons, there were a lot of people who used to sell those. But with EBT, you can’t just sell the card -- you’d also have to give the buyer your PIN number. And you’d have to trust they were going to bring the card back to you.

There’s a story I like to tell about a SNAP presentation I was giving to a group of farmers. One guy in the audience stood up and said that, in his community, people sold their EBT cards outside of grocery stores. He claimed to have purchased one, if I remember.

And I kind of paused and said, so -- did that person also give you his PIN number? Because you can’t use the card without it. And I said -- do you realize that was a federal offense? Then he kind of backed down: “Oh, actually I didn’t buy the card, I heard about it from someone else.”

So maybe people aren’t selling their EBT cards -- but could they buy groceries with benefits and then sell them for cash? I hear from readers, for instance, who say they see people buying baby formula and reselling it.

There’s a couple things going on here. The first thing, with infant formula -- I think they are probably thinking about the Special Supplemental Nutrition Program for Women, Infants and Children (WIC). Theoretically, you could have someone who doesn’t tell the WIC person they’re breastfeeding so that they still get infant formula. But those are totally separate programs. Sometimes people lump the two things together.

With respect to SNAP -- I can’t make sense of that, from a rational standpoint. Presumably, in this scenario, people are buying groceries with SNAP and then reselling those groceries at a lower price than what they cost in the store. Most off-SNAP purchases are inframarginal, meaning that they spent more than their benefit amount on food. So if someone sold their benefits, they would be giving up the opportunity to purchase food, and would have to purchase food with other funds.

The only group of people who this might make economic sense for are those who are not inframarginal -- meaning they only spend $100 per month on food and they get $120 per month in SNAP benefits. They could sell that extra $20 of food they get on benefits. But even if that was happening, it would be such a small proportion of people. Who cares?

Well -- a lot of people care! I think there’s a sense that these are their tax dollars, so they have some vested interest in how they’re spent.

But SNAP participants are also taxpayers -- often at a higher rate, relevant to their income. And even if they aren’t taxpayers now, they were taxpayers at one point in their lives. Now this is an insurance program for them. So I say yes, these are your tax dollars -- but if you run into hard times, you can also get these benefits. We certainly don’t have perfect insurance markets.

What about people who aren’t necessarily taxpayers? -- or not income taxpayers, at least. There is a prominent belief that undocumented immigrants can access SNAP, and that some actually come to the U.S. to get these benefits.

In terms of how many undocumented people are eligible for SNAP -- none. And I’ve not seen any evidence that there’s wholesale participation by undocumented persons.

However the children of undocumented immigrants who are legal U.S. residents, or other household members who are legal U.S. residents, they have as much right to these benefits as anyone else. So there might be some spillover there. But undocumented persons are not themselves getting SNAP benefits, because they’re not eligible for them.

One last anecdote I hear a lot: the case of the SNAP participant who uses their benefits to buy groceries, and then walks out to a $100,000 car.

Yeah, the old myth of the guy pulling up in the Caddie to pick up groceries. Well, today it’s probably more like a Range Rover.

If you look at the average income of people on SNAP benefits, it’s just not true that they’re wealthy. And moreover -- at least historically -- many states have had an asset test for SNAP. A car above $4600 is a disqualifying asset. So if someone is driving a Caddie or a Range Rover, they would be ineligible by definition. Unless they’re borrowing a friend’s.

That’s another thing I always say to people: How do you know who owns the car, or the circumstances of the person who bought it? These people are paying a lot of attention to someone in the checkout line, and then following them out to the parking lot to see what kind of car they drive, and then guessing whether it’s their car or whatever else.

You know, there’s a large number of SNAP participants who are temporarily down on their luck. Maybe they did have a nice car before and they’re still driving it. Do you want them to sell the car? I don’t know. But the length of SNAP participation is only seven to nine months on average.

It seems, based on the rhetoric I hear, that a lot of people believe SNAP is more of a long-term program.

No. SNAP is just so successful at what it does. It sets out to alleviate hunger and it does. I think there are a lot of government programs we could get rid of, and SNAP is not one of them.

But if SNAP does work as well as you believe, why is it often a political target ...?

I think these stories get told. I really do. And that’s unfortunate.

More from Wonkblog:

The GOP poverty agenda, decoded

What happens when a family runs out of food stamps

How 20 years of welfare reform have changed American poverty