To improve patient care, doctors rely on research and published information.

According to an American Medical News report, professional journals are still the most popular source of up-to-date medical information among doctors.

These medical publications inform physicians on new drugs and treatments, and they contain peer-reviewed studies that both physicians and patients assume are scientifically accurate.

But all too often, research findings aren’t as scientific as they should be. And some are flat-out biased.

Research studies confirm bias in research

In 2012, the report “Industry sponsorship and research outcome” concluded that studies sponsored by a drug or device company lead to “more favorable results and conclusions” about the products studied than independently sponsored ones.

And a recent study from the Harvard Medical School on plastic surgery outcomes concluded, “Studies authored by groups with conflicts of interest are significantly associated with reporting lower surgical complications and therefore describing positive research findings.”

This was especially true when manufacturer-marketed products were used in the study, according to the study’s abstract.

Perhaps the most damning study comes by way of the National Center for Biotechnology Information.

In it, the authors identified 24 peer-reviewed studies published in highly respected medical journals. Each study compared two different types of suction devices that help wounds heal faster.

One device uses a sponge-type material while the other relies on a gauze-wound interface.

The researchers asked five independent surgeons to read all 24 papers and determine which product was judged as better in each study.

The conclusion: Seven papers seemed to favor the first treatment, 15 favored the second and 2 didn’t reach a definitive judgment.

Now, here’s the kicker

Of the 24 studies, 19 were funded by a manufacturer of one of the two devices. Lo and behold, based on determinations made by the independent surgeons, 18 of those 19 papers recommended the product made by the manufacturer who funded the research. Just one manufacturer-funded study was deemed to have a neutral conclusion.

From a statistical perspective, this is nearly an impossible outcome.

Flip a coin 19 times and there’s a 1 in 524,288 chance it comes up heads each time.

We might expect that if the two alternative products were relatively equivalent and the research truly unbiased, the product sold by the non-funding company should come out on top about half the time. To have no study go against the funding company yields nearly impossible odds.

And if they are not equivalent, the better product should be identified in nearly all studies, regardless of the source of the researcher’s funding.

There is no way to interpret these results, except to assume the researchers themselves were biased based on who paid for their work.

Biased outcomes like these would raise red flags in any other context. They would have signaled some sort of inappropriate influence. The scientific results would have been rejected by medical journals.

But not under these circumstances.

How bias gets by in medical research

No manufacturer is foolish enough to demand that investigators reach a specific conclusion in their research. Discovery of such a quid pro quo relationship could result in a major scandal for the company and the termination of the researchers.

The origin of bias in these manufacturer-funded studies may be subconscious, but no less effective.

Researchers and research sponsors interact at events and meetings during the time the work itself is being performance and during subsequent clinical trials.

And social science literature has clearly demonstrated people have a strong desire to reciprocate a gift.

At a minimum, grateful researchers unconsciously want to “return the favor” to their funding organizations.

And given the constant pressure in academia to “publish or perish,” this bias could be more overt as researchers fear losing funding – even if a threat is never explicitly conveyed.

Regardless of the etiology, research bias and skewed results are real when medical companies fund studies on their products. And whether it’s conscious or unconscious, bias is inappropriate in any scientific context.

Curbing bias in medical research 

Over the past decades, attempts have been made to limit the inappropriate influence of bias in research.

Today, authors of peer-reviewed articles and presenters at accredited meetings are required to disclose any personal financial benefit from the research. They must also disclose financial dealings with the manufacturer – but not any of the details.

Researchers receiving federally funded grants must register their trials on ClinicalTrials.gov and publish their results even when findings don’t favor the funding organization.

The days of sponsors suppressing unfavorable outcomes or helping investigators write their papers before submission are largely behind us.

But as the data demonstrate, today’s system is far from effective at ensuring scientific integrity.

The negative consequences of manufacturer-funded research

Physicians rely on published data to determine the best treatment for their patients. When it is contaminated by inappropriate influence, doctors can’t provide the best possible care.

As a result, patients end up with lower quality care, increased complications and higher costs.

Public and private entities could take a number of big steps to curb medical research bias.

For starters, peer-reviewed journals could refuse to publish articles funded by a single company.

If manufacturers wanted to advance medical knowledge, competing drug and device companies could contribute to a common, independent research fund for their particular industry. This would eliminate the manufacturer-researcher relationship from a study’s equation.

Alternatively, a small fee could be added to the sales price of medical devices and drugs to fund independent research. Organizations like the National Institute of Health (NIH) could oversee the distribution of these dollars.

Of course, we should expect manufacturers to resist such changes. After all, drug and device companies aspire to drive product sales, not produce unbiased research.

But the problems created by the current system are far too serious to accept the status quo.

We need to stop hiding our heads in the sand. The data is clear. Change is essential.

Robert Pearl is a physician and CEO, The Permanente Medical Group. This article originally appeared on Forbes.com.