Manipulating the government's monthly unemployment report is impossible because of the large number of people -- mostly civil servants and not political appointees -- involved in compiling the data, said the former commissioner of the Bureau of Labor Statistics.

"I think it would be impossible to really manipulate the numbers," said Keith Hall, who served from 2008 to 2012 as commissioner of the independent statistical agency, which produces the report. "Certainly, it would be impossible to manipulate the numbers and not be found out."

After the BLS reported Friday that the unemployment rate in September dropped to 7.8 percent from 8.1 percent, former General Electric Chief Executive Jack Welch charged that the White House manipulated the number to distract from President Obama's debate performance this week. "Unbelievable jobs numbers ... these Chicago guys will do anything ... can't debate so change number," Welch tweeted.

Hall, who was appointed by former President George W. Bush and served through much of the Obama administration, said the BLS commissioner is a nonpolitical position. The commissioner serves a four-year term and is not replaced by an incoming president, as the heads of Cabinet departments and other agencies are.

"I feel like I'm a certified economic geek rather than a political person," said Hall, who is a senior research fellow at the Mercatus Center at George Mason University.

During his four years as commissioner of the BLS, which is part of the Labor Department, Hall said he was never asked by the Bush or Obama White House to change any data.

The unemployment rate is calculated differently than the monthly job-growth figure. To determine the rate, Census Bureau employees survey about 50,000 people each month -- mostly over the phone but sometimes in person -- to determine if they are employed, Hall said.

Dozens, if not hundreds, of people are involved in collecting the data and compiling it, he said. The household survey data are more volatile than the monthly payroll figures on job growth, which are compiled from about 400,000 businesses, he said. But the household survey can be an early indicator of changes in the jobs market because it can take a while for new businesses to be included in the payroll survey.

"At turning points, sometimes the household survey turns a little quicker than the payroll survey does," Hall said. "It doesn't mean it doesn't give out false signals."

If the September household survey is picking up a trend, Hall said he'd expect job creation to increase during the next couple of months. If September was more of a statistical fluke, the unemployment rate would go up.