We’ve been keeping a close eye on the controversy surrounding McKinsey & Company and the firm’s report on the Affordable Care Act. To briefly recap, McKinsey published a highly dubious study showing nearly a third of American businesses will stop offering health coverage to their employees as a result of the new reform law, but the company refuses to disclose its methodology or subject its findings to any scrutiny.

One of the main arguments from the White House has been that the McKinsey findings are at odds with all available evidence, including independent research from the Congressional Budget Office, the Rand Corporation, and the Urban Institute. Today, Greg Sargent advances this quite a bit with an amusing revelation.

The White House has pointed to various studies finding the opposite of what McKinsey’s study found in order to make the case that it’s an outlier that should not be taken seriously. But Sam Wainwright ferrets out a gem: It turns out that one of those studies was written by someone who is now a chief analyst of health reform at … McKinsey.

Yes, it turns out that some of the evidence to disprove the controversial report from McKinsey & Company was published by a McKinsey & Company analyst.*

How unfortunate for them.

What’s more, as interest in this story slowly but surely spreads, demands that the firm come clean are getting louder. One powerful senator in particular wants answers.

The pressure on McKinsey to explain its latest study critical of the healthcare reform law grew substantially Thursday after Senate Finance Chairman Max Baucus (D-Mont.) demanded answers ahead of a meeting with the consulting firm. […]

“Honest public discourse requires a standard level of transparency — one McKinsey simply has not met,” Baucus said in a statement accompanying his demand for McKinsey to release its survey methodology. “The conclusions McKinsey reached differ sharply from results of other reputable, transparent research on the subject. McKinsey’s findings also counter what actually happened in Massachusetts when similar policies increased employer-sponsored health insurance. We all want the most accurate information and the ability to evaluate its integrity, which is why McKinsey should answer these basic questions.”

McKinsey has agreed to meet with the committee to explain its report.

That should be an interesting discussion, though it’s not yet clear if the meeting will be public. I rather doubt that it will.

In the meantime, Baucus’ office has already written a letter to McKinsey’s global managing director with a series of questions that the senator would like to see answered. Among them: who funded the study, will McKinsey benefit financially from the results, how was the survey was structured, how were participants chosen, how were the interviews conducted, how were respondents “educated,” what was the exact wording of the questions, what was the internal review process like, and many others.

“Providing the public and policymakers with the necessary information to evaluate the integrity of publicly released survey conclusions,” the letter says, “is essential to honest public discourse.”

And as I go to publish this, it also appears that three House committees are pressing McKinsey for the same information. As Greg noted, “It isn’t every day that the chairman of the Senate Finance Committee and three House committees simultaneously demand that a company cough up the internals of a survey like this one.”

I wonder how much more it will take before major news outlets take more of an interest in this.

* fixed

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.