OMB director Mick Mulvaney prepares to testify at his confirmation hearing before the Senate Budget Committee on Jan. 24. (Jim Lo Scalzo/European Pressphoto Agency)

Mick Mulvaney, President Trump's budget director, accused the Obama administration on Sunday of doctoring federal data to minimize the number of Americans out of work.

“We've thought for a long time, I did, that the Obama administration was manipulating the numbers, in terms of the number of people in the workforce, to make the unemployment rate — that percentage rate — look smaller than it actually was,” Mulvaney told CNN's Jake Tapper.

It was the latest attack from a string of Republicans — including President Trump — who have said the monthly jobs reports were fake or unreliable, contradicting economists who say federal data on business in the United States is some of the most trustworthy in the world.

The agencies responsible for collecting that data observe strict rules designed to prevent politicians from cooking the books, and Erica Groshen, the commissioner of the Bureau of Labor Statistics under President Obama, rejected the accusation. “If he is talking about actual interference with the process that ensures the integrity of the data, then he’s mistaken,” she said.

Now that Mulvaney is in charge of the Office of Management and Budget, he has the opportunity to put the issue to rest, one way or the other. He and other skeptics in Trump's new administration have the authority to demand the evidence that they would support their claims about manipulation — evidence that they have not provided so far.

In his new position, Mulvaney is legally responsible for coordinating statistical work across the federal government. He supervises the department that sets standards for all the agencies that collect and report data, including the Bureau of Labor Statistics, which publishes the monthly report on employment.

The bureau's publications are also periodically audited by the Labor Department's inspector general and by the Government Accountability Office. Mulvaney could request an audit, as could Trump's nominee for labor secretary, Alexander Acosta, if he is confirmed.

These audits are part of the government's continuing efforts to ensure that official data are immune to political interference and to help keep the process up to date in response to changing technology and an evolving economy, Groshen said.

“BLS data have not been manipulated by previous administrations,” she said. “Not by the Obama administration, nor by the Trump administration.” (Obama's first BLS director, Keith Hall, was first put in the position by former president George W. Bush and is now head of the Congressional Budget Office.)

Many Republicans and some Democrats have argued that the bureau distracts from more important issues by concentrating on the unemployment rate — a measure of how many people are looking for work, compared to how many are employed. The data also show that there are fewer people in the labor force overall, including both those who are looking for work and those who are working, in part due to increasing discouragement and disability among workers.

In his comments Sunday, Mulvaney seemed to go further. Rather than arguing that the size of the labor force is more informative than the unemployment rate, he suggested that the Obama administration had manipulated data on the labor force.

“Any user of data is entitled to interpret the data as they see fit, and to choose to highlight that they find most useful,” Groshen said, “but that’s not manipulation.”

During his confirmation hearing in the Senate, Mulvaney implied that he would serve as a voice of moderation in the Trump administration and that he would insist that the president confront the hard arithmetic of the federal budget and the national economy.

“The credibility that I think I bring to this job is that I believe very firmly in real numbers,” Mulvaney said. “My job is to tell the president the truth. My job is to tell you the truth.”