According to some of the economists cited in his report that slammed the federal safety net, GOP Rep. Paul Ryan either misrepresented or misunderstood data that he used in the 204-page study.

The report, titled “The War on Poverty: 50 years later,” was released this Monday and pointed out that the U.S. poverty rate has remained at 15 percent.

“And the trends are not encouraging,” Ryan wrote in the report. “Federal programs are not only failing to address the problem. They are also in some significant respects making it worse. Changes are clearly necessary, and the first step is to evaluate what the federal government is doing right now.”

But some authors of the research Ryan cited are crying foul, accusing the former vice presidential candidate of ignoring statistics that show government aid programs have actually been a success.

One of the studies Ryan sited was from the Columbia Population research Center that measured the decline in poverty in the last 5o years. According to The Fiscal Times:

One of the study’s authors, Jane Waldfogel, a professor at Columbia University and a visiting scholar at the Russell Sage Foundation, said she was surprised when she read the paper, because it seemed to arbitrarily chop off data from two of the most successful years of the war on poverty.

Waldfogel and her colleagues looked at an alternative measure of the poverty rate known as the Supplemental Poverty Measure (SPM), which factors in government benefits like food stamps and programs like the earned-income tax credit. That alternative measure is thought to present a more accurate and realistic gauge of the poverty and the real-world effects of government programs aimed at combatting it.

The Columbia study found that the poverty rate fell from 26 percent in 1967 to 15 percent in 2012. Ryan’s report only used data starting from 1969 – excluding a full 36 percent.

Ryan’s report says the authors find that “recipients initially experience an average annual decline in earnings of $858 in the initial year of voucher receipt. However, the negative income effect decreased to $277 five years after voucher receipt.”

“This is misstated,” Wolfe said in an email. “Our findings are a decrease of $598 NOT his $858 and in five years the decrease we estimate is $47.46 (which is not statistically different from zero).”

A spokesperson for Ryan said he welcomed the criticism because it encourages debate.

“This report will help start the conversation,” Ryan said Monday. “It shows that some programs work; others don’t. And for many of them, we just don’t know.”