Mike Griffith, of Canton, Ga., holds a sign during a protest against President Barack Obama's health care reform plan outside the 11th Circuit Court of Appeals in Atlanta, Wednesday, June 8, 2011. A three-judge panel of the 11th Circuit Court of Appeals was hearing arguments on whether to reverse a Florida judge's ruling that struck down the law. (AP Photo/John Bazemore)

(CNSNews.com) – Top House Democrats are going on the offensive against business consulting firm McKinsey & Company over a study the company conducted that found that significant numbers of employers would stop offering health insurance due to Obamacare’s mandates.

The McKinsey study found that 30 percent of employers would “definitely or probably” stop offering their employees health insurance due to Obamacare’s minimum coverage mandate for employers with 50 or more employees.

That finding is at odds with other studies conducted by the CBO, Rand Corporation, and Urban Institute that all suggested a much smaller effect on employer-provided insurance.

Democrats seized on this discrepancy in launching their attacks on McKinsey, trying to discredit the study by pointing to the fact that the firm refuses to release the raw data it used.

“Indeed, the findings of this survey are so markedly out of sync with other assessments that it has raised legitimate questions about the product, including how and why it was created,” senior House Democrats said in an official letter to McKinsey & Company Thursday.

“Refusing to release the underlying questions and methodology undermines the credibility of the findings. We are concerned that, if the survey based its conclusions on a questionable instrument and potentially biased methodology, McKinsey may have provided the American public with invalid information about the impact of the Affordable Care Act.”

By making an issue out of the study’s methodology, Democrats hope to cast doubt on its findings. In their letter, the top House Democrats including Reps. Henry Waxman (D-Calif.), John Conyers (D-Mich.), Sander Levin (D-Mich.), Rep. George Miller (D-Calif.) demanded to see not only the study’s methodology, but the names and resumes of the researchers who produced it, and information on how much money McKinsey spent to produce it.

Notably, the Democrats made an issue of the fact that McKinsey claimed to have “educated” respondents on the effects of Obamacare. In its initial report, McKinsey cited this education as a reason their study reached different conclusions from other studies.

“Our survey shows significantly more interest in alternatives to ESI than other sources do, for several reasons. Interest in these alternatives rises with increasing awareness of reform, and our survey educated respondents about its implications for their companies and employees before they were asked about post-2014 strategies,” McKinsey said of the study.

Democrats suggested that by informing respondents of the effects of Obamacare, McKinsey had somehow biased them against the law.

“The report itself states that McKinsey “educated respondents” about the implications of the Affordable Care Act, with no indication of the content of this “education.”

Democrats demanded to see the materials McKinsey used to educate its respondents about the effects of Obamacare, including the scripts investigators used when speaking to respondents.

“All documents related to education of respondents conducted by McKinsey or its agents

as part of the survey, including any scripts or written materials used in this process,” they wrote.

McKinsey has refused calls from Democrats to produce the study’s underlying data and methods, saying that the information is proprietary. The House Democrats wrote that they only wanted to see “summary” information on survey respondents, conceding the point that the companies survey by McKinsey had probably done so on condition of anonymity.

“We understand that companies may have responded to the survey under the assumption that their individual responses would be kept confidential. We therefore wish to clarify that…we are asking only for summary information and are not seeking the names or survey results of any individual survey respondent,” they wrote.

The senior Democrats said they expected McKinsey to produce the information by July 5.