Washington - A new study by the Agriculture Department has found that food stamps, one of the country's largest social safety net programs, reduced the poverty rate substantially during the recent recession. The food stamp program, formally known as the Supplemental Nutrition Assistance Program, or SNAP, reduced the poverty rate by nearly 8 percent in 2009, the most recent year included in the study, a significant impact for a social program whose effects often go unnoticed by policy makers.
The food stamp program is one of the largest antipoverty efforts in the country, serving more than 46 million people. But the extra income it provides is not counted in the government's formal poverty measure, an omission that makes it difficult for officials to see the effects of the policy and get an accurate figure for the number of people beneath the poverty threshold, which was about $22,000 for a family of four in 2009.
"SNAP plays a crucial, but often underappreciated, role in alleviating poverty," said Stacy Dean, an expert on the program with the Center for Budget and Policy Priorities, a Washington-based research group that focuses on social programs and budget policy.
Enrollment in the food stamp program grew substantially during the recession and immediately after, rising by 45 percent from January of 2009 to January of this year, according to monthly figures on the U.S.D.A. Web site. The stimulus package pushed by President Obama and enacted by Congress significantly boosted funding for the program as a temporary relief for families who had fallen on hard times in the recession.
But the steady rise tapered off in January, when enrollment was down slightly from December, a change in direction that Ms. Dean said could signal that the recovery was having an effect even among poor families.
The program's effects have long been known among poverty researchers, and for Ms. Dean, the most interesting aspect of the report was the political context into which it was released. In a year of elections and rising budget pressures, social programs like food stamps are coming under increased scrutiny from Republican legislators, who argue that they create a kind of entitlement society.
In an e-mail to supporters on Monday, Representative Allen B. West, a Florida Republican, called the increase in food stamp use a "highly disturbing trend." He said that he had noticed a sign outside a gas station in his district over the weekend alerting customers that food stamps were accepted.
"This is not something we should be proud to promote," he said.
Kevin W. Concannon, the under secretary of agriculture for food, nutrition and consumer services, argued that since the changes to the welfare system in the 1990s, the food stamp program was one of the few remaining antipoverty programs that provided benefits with few conditions beyond income level and legal residence.
"The numbers of people on SNAP reflect the economic challenges people are facing across the country," Mr. Concannon said. "Folks who have lost their jobs or are getting fewer hours. These people haven't been invented."
The study, which examined nine years of data, tried to measure the program's effects on people whose incomes remained below the poverty threshold. The program lifted the average poor person's income up about six percent closer to the line over the length of the study, making poverty less severe. When the benefits were included in the income of families with children, the result was that children below the threshold moved about 11 percent closer to the line.
The program had a stronger effect on children because they are more likely to be poor and they make up about half of the program's participants.
"Even if SNAP doesn't have the effect of lifting someone out of poverty, it moves them further up," Mr. Concannon said.