As nurse practitioners lobby to expand their authority and scope of practice in many states, a New England Journal of Medicine study released Wednesday documents a deep chasm between how doctors and nurses regard the issue.

The study found the two groups overwhelmingly agreed that nurse practitioners should be able to practice to the full extent of their schooling and training. But doctors were less likely to concur that advanced practice nurses should lead medical homes, which deliver team-based, coordinated care to patients. Only 17 percent of the 505 primary care physicians  surveyed agreed with that notion, compared to 82 percent of the 467 nurse practitioners surveyed.

The two groups also disagreed about whether nurse practitioners should be paid equally for providing the same health services. More than 64 percent of nurse practitioners agreed with the idea of equal pay, as opposed to less than 4 percent of doctors.

The debate over the role of nurse practitioners has intensified as a result of concerns over a shortage of doctors as an estimated 25 million people gain insurance under the health care law.  Nurse practitioners argue they can fill some of those needs if they are granted greater scope of practice.

That debate is reflected in the study’s finding about the groups’ conflicting views about the quality of care provided by doctors versus nurse practitioners. When researchers asked whether they felt the quality of care provided by physicians in exams and consultations was higher than that provided by nurse practitioners, more than 66 percent of doctors agreed, while 75 percent of nurses disagreed.

“We’ve done a lot of comparative surveys with health professionals but we’ve just never found gaps this big,” said Dr. Karen Donelan, an assistant professor of medicine at the Harvard School of Medicine and the study’s lead author. “When we get on the ground and we survey the people actually doing the work and working together, we see some of those professionals come closer together. We didn’t observe that here.”

Donelan pointed out that most nurse practitioners in the study — approximately 75 percent — said they are already practicing to the full extent of their training. Survey respondents who did not have this opportunity blamed their limited practice on state restrictions, hospital regulations and work setting.

During an interview, Donelan also said she was surprised by the level of disagreement in regards to the quality of care, since previous research findings have suggested little variation in the work done by  nurse practitioners and primary care doctors.

During a February 2013 interview, David Hebert, the CEO of the American Association of Nurse Practitioners, described the safety concerns raised by physicians as a “total red herring,” and added that “nurse practitioners have been practicing safely and providing great outcomes for decades.”

In March, the president-elect of the American Academy of Family Physicians, Reid Blackwelder, emphasized his support for a more collaborative approach between the two clinician groups, noting their roles are not interchangeable.

Differences aside, Donelan’s study shows that the majority of practitioners in both groups agreed that increasing the number of nurse practitioners would improve timeliness of care. However, less than a third of doctors said such an increase would boost safety or effectiveness of care.

Nurse practitioners, on the other hand, overwhelmingly felt such an increase would improve care. Close to 81 percent, for example, thought the growth would improve access to health care for the uninsured and 77 percent said it would result in lower health care costs.

“As a team, this kind of inter-professional disagreement is not a good thing when we’re trying to achieve better teamwork,” Donelan said. “The conflict over roles has got to be worked out so that it’s clear for patients when they get their care.”

Moving forward, she said she hopes that both doctors and nurse practitioners will acknowledge their differences and bridge the gaps that keep them from working together.