"We estimate that only 10-15 percent of health care decisions are currently evidence-based," said Melnyk. "We are a long way off using the best evidence we have and putting that into practice."
Doctors weren't the only ones up in arms. Plenty of activists, politicians and bloggers have taken issue with Monday's recommendations that also double the time between routine mammograms for women over age 50 to once every other year.
In this case, Melnyk and another member of the task force say the reaction may be due to misinterpretations than professional disagreements about the guidelines.
"I think what everybody needs to understand is that our recommendation is not a recommendation against screening women in their 40s,"said Melnyk. "It's recommendation against routine screening starting at age 40."
In other words, Melnyk said women should not start getting mammograms automatically when they turn 40, but instead talk with their doctors about their personal risks for breast cancer to see if a mammogram is warranted.
She said one of the biggest misperceptions "is that the United States Preventive Task Force is a government agency. We are not. We are not hired by the government to put out these recommendations. We are truly a group of independent experts," said Melnyk.
Task force member Dr. Timothy Wilt said the motivations behind the recommendations have also become a point of confusion and charges of health care rationing.
"There are some individuals who don't like the message and they want to turn it into a message of access and cost," said Wilt, of the Minneapolis Veterans Affairs Medical Center in Minnesota.
However, Wilt said the task force did not consider cost or insurance at all in their recommendations. Instead he hoped the recommendations would represent the best analysis of the harms versus benefit equation in breast cancer screening.
Wilt also pointed out that the task force believes there are serious harms in the practice of giving mammograms to every woman in her 40s, regardless of her risk for breast cancer.
For example, 100,000 women in their 40s are screened. "That means that there will be 5,000 biopsies which cause some pain and additional anxiety and additional radiation associated with additional testing."
However, at least in the first week, the guidelines have caused more anxiety for doctors and patients confused by the guidelines.
Dr. Susan Boolbol of the Beth Israel Medical center in New York had one patient cancel a lumpectomy this week because she mistook the task force's guidelines on screening as a free pass for women in their 40s.
"In light of the article about mammograms and "overtreatment" of breast cancer, this patient had decided to forego a surgery. She believes that removing this [cancerous] area is too radical a treatment," Boolbol told ABC News. "It is difficult for the lay person to fully understand what these studies really mean and how decisions about recommendations and guidelines are made."
Below is a list of medical centers that told ABC News they will stick with current guidelines recommending breast cancer screenings begin at age 40. Click the links below to read their statements.
Beth Israel Medical Center, New York