Dressed in a crisp, dark suit, a Carolina blue tie snug against his neck and with dirty-blond stubble dotting his chin and upper lip, Kevin Guskiewicz stood before a podium in a conference room at the University of North Carolina at Chapel Hill’s department of exercise and sport science and introduced a special guest speaker.

“I’m proud to call Roger Goodell a friend and a colleague,” Guskiewicz said in his introductory remarks on March 6, 2013, “someone with whom I’ve sat at the table, rolled up our sleeves and tried to tackle some of the most serious issues around health and safety for players.”

At the time, Goodell, the NFL commissioner, was at the peak of his popularity. A massive class-action concussion lawsuit against the league had been filed by former NFL players in 2011 and media stories critical of Goodell had been published, but the concussion crisis hadn’t yet engulfed the sport. And the Ray Rice video showing the Ravens player assaulting his then-girlfriend had yet to surface, a shocking incident that increased scrutiny over the NFL’s mishandling of incidents of domestic violence. Three months prior to his talk at UNC, Goodell was Time magazine’s cover subject ­– the headline, “The Enforcer” emblazoned in red across his chest.

Guskiewicz was a star of equal brightness in his field, and although he didn’t grace Time’s front page like Goodell, the magazine called Guskiewicz a “game changer” in a 2013 feature in which he was profiled with more than a dozen other “innovators and problem-solvers that are inspiring change in America.”

“Through his research on sport-related concussions, Dr. Kevin Guskiewicz is literally changing the game – from innovative sideline tests in football to the study of long-term effects in all sports,” the Time blurb read.

A certified athletic trainer who early in his career worked for the Pittsburgh Steelers, Guskiewicz was hired by UNC in 1995 and later he became the founding director of the university’s Matthew Gfeller Sport-Related Traumatic Brain Injury Research Center (named after a North Carolina high school football player who died in 2008 after suffering a TBI on the field). Guskiewicz quickly became one of the leading scholars in concussion research. In 2011, Guskiewicz was awarded a prestigious MacArthur Fellowship – a “genius grant” – and $500,000 to further his work.

Thanks to Guskiewicz, UNC had one of the country’s leading concussion/TBI research centers by 2013. He collaborated with the NCAA and NFL on numerous issues involving player safety. He served on the NFL’s influential Head, Neck and Spine Committee. So well regarded was Guskiewicz in the concussion/TBI field of research that he exchanged several emails with the NFL’s then-communications chief Greg Aiello weeks before Goodell’s arrival on campus that shaped Goodell’s presentation. “Please don’t worry about lifting any of this and making these ‘Rogers’ (sic) words,’” reads part of an email Guskiewicz wrote to Aiello. Throughout his talk, Goodell used snippets of Guskiewicz’s suggestions, sometimes verbatim.

Yes, Guskiewicz’s clout was such that he could put words directly into the NFL commissioner’s mouth.

At the time of Goodell’s speech, Guskiewicz and his research also stood out as a much-needed positive on a UNC campus mired in scandal. A 2012 report written by former North Carolina governor Jim Martin laid bare sprawling academic fraud. Student-athletes had, for years, enrolled in bogus courses known as “paper classes” in the African and Afro-American Studies department. A 2014 independent investigation conducted by a former Justice Department official only further sullied the school’s reputation.

UNC could point to Guskiewicz and his research as evidence of what was right at the school. Later, he became the dean of the College of Arts & Sciences and then, this past February, he was named UNC’s interim chancellor.

But now, like Goodell before him, Guskiewicz’s credibility has been called into question, as has the concussion research he and others working with him have generated for years. A paper published in June in the Journal of Scientific Practice and Integrity (JoSPI) details abnormally high rates of learning disability (LD) and attention deficit hyperactivity disorder (ADHD) diagnoses among incoming UNC football players over a nine-year stretch, evidence of possible gross misuse of stimulant medication by UNC athletes, and the use of LD/ADHD athletes as UNC test subjects in concussion/TBI research. The last detail is most consequential as it pertains to Guskiewicz, as he and others failed to disclose or account for that criteria in many published peer-reviewed articles, which is standard practice in concussion research.

[Listen to The Lead: UNC’s Concussion Research May Not Be Reliable]

Over the past nine months, The Athletic gained access to research done by Ted Tatos, a University of Utah adjunct professor and economist, and Donald Comrie, the chief executive officer of NeuroLabs, a Manhattan-based scientific management and consulting company focused on the central nervous system. They authored the JoSPI paper, “Cognitive Deficits and LD/ADHD Among College Football Athletes and Undisclosed Inclusion in Concussion Research” that published in June. The Athletic also interviewed more than a dozen physicians, scientists and experts in concussion/TBI research for a three-part video documentary – anchored by The Athletic’s Armen Keteyian – and for this article.

At the heart of the 11,000-word paper authored by Tatos and Comrie and evident throughout the reporting done by The Athletic, is the alarming possibility that decades of work on concussion research, data used by the NFL, NCAA schools, and even the Department of Defense, may now be invalid. They found 11 concussion papers that used UNC football players drawn from the same study groups over a nine-year period with abnormally high ADHD rates. But that critical modifying factor was never disclosed in papers that appeared in prominent scientific journals. Ten of those papers were co-authored by Kevin Guskiewicz.

“I’m not diagnosing these people, and I’m not saying I’m an expert in diagnosing ADHD,” says Tatos. “I am an expert in statistics. And I am an expert in doing research. I know bad statistics when I see it … I do think there’s some evidence of scientific misconduct and that some of those papers need to be reviewed and retracted.”

Adds Comrie, who has worked with the NFL Players Association in concussion settlement matters: “What is an even greater scare to me, how many people cited (these papers)?”

Roger Goodell speaks at UNC in 2013. (Gerry Broome / AP Photo)

Ted Tatos was born in Romania in the early 1970s, an only child who grew up during the totalitarian regime of Nicolae Ceausescu. Tatos says his parents – his late father was a professor and was jailed as a political prisoner during the Communist reign – and he left the Eastern Bloc country when Tatos was 10. They immigrated to North Carolina where they lived in faculty housing at Campbell University, in tiny Buies Creek. Tatos’ father taught at the private Baptist school, and his mother earned a graduate degree from UNC and later taught French and English.

Tatos, 47, has worked in the field of economics for almost a quarter-century – he got his start with the global economics consulting firm, LECG, in Washington D.C., and later moved to Salt Lake City – focusing on antitrust issues. Hired as an expert witness in numerous state and federal court cases, Tatos says his attention turned toward UNC athletes after he read about the school’s academic fraud scandal and learned that the university would be making a trove of documents public.

Starting in 2015, UNC began to upload the information to a public portal – nearly two million documents that the university released after media outlets made public records requests.

For more than three years, Tatos combed through emails, reports, spreadsheets, tables and other data with the precision of a forensic analyst. He says initially, “I was analyzing this (UNC) data because of antitrust issues surrounding college athletics, whether NCAA schools have colluded to constrain compensation for athletes.”

But he stumbled upon documents detailing abnormally high percentage rates of UNC athletes with LD/ADHD from 2004 to 2012, a stretch when UNC was trying to revamp its football program. The percentages were consistently three to four times greater than the national average.

In one email from 2007, for example, neuropsychiatrist Thomas Gualtieri, hired by the school as an outside contractor, revealed that among a group that included incoming football players from the previous two years and women’s basketball players from the previous year, 61 percent “had either ADD or a learning disability (or both), and the large majority were previously undiagnosed.”

A paper co-authored by the NCAA’s chief medical officer, Brian Hainline, and published this year says “the prevalence of ADHD in student-athletes and elite athletes may be 7 percent – 8 percent.”

Based on the UNC documents, generally only scholarship athletes were eligible for learning disability testing. And an internal review found that among about 180 UNC athletes tested between 2004 and 2012 – including 137 scholarship football players – there was a “39 percent incidence of LD and or ADHD.”

“If that’s an accurate number, that (does) seem high to me,” says Hainline, a neurologist. “‘Cause it’s unusual for ADHD or LD to somehow just manifest in college. It almost always has manifest already in high school, very often in grade school. It’s unusual just for it to start in college.”

But that’s exactly what Ted Tatos found was happening at UNC. An overwhelming majority of the athletes tested between 2004 and 2012 were diagnosed with ADD, LD or ADHD for the first time at Chapel Hill.

When Tatos dug deeper into the UNC documents, he found that not only were the high LD/ADHD rates not an anomaly and not specific to one year but that a high percentage of athletes were also being prescribed ADHD medication. While the total number of UNC football players receiving ADHD medication is unclear, a 2009-2010 end-of-year report showed that 16 of 23 freshman football players (70 percent) were prescribed medication.

Mary Willingham was a learning specialist inside the athletic department between 2003 and 2010, working with the neuropsychologists responsible for LD or ADHD testing at UNC. She says there was pressure from coaches to keep players academically eligible to compete, and that diagnosing football players with a learning disability or ADHD was helpful in those efforts.

According to the UNC documents Tatos reviewed, a diagnosis of ADHD often came with special accommodations, including personal note-takers, untimed tests and prescriptions for stimulant medications such as Adderall or Ritalin, which are otherwise banned by the NCAA as performance-enhancing drugs.

In a 2006 email, the issue of ADHD medication among football players set off alarms inside the UNC athletic department. The head athletic trainer expressed concern that “some of our student-athletes are being put on medication that is not documented by student health and our team physician.”

In another email in which the date is redacted, Mario Ciocca, a team physician at UNC, wrote to Willingham and others about a male athlete – his name is also redacted -– who experienced “palpitations” after taking “Adderall before a morning run … ”

“He says he was told the medicine would help him out with practice and I think he interpreted that as he should take his med before practice,” Ciocca wrote. “I know that he was not told by anyone to take it before practice but that’s just how he interpreted it. Please pass on to prescribers so that they are aware that the athletes might have this perception.”

Says Willingham: “Athletes would come in and ask if they can test for ADHD because they were interested in taking the medication as well because they could see that that teammate was able to get more work done or you know, take some, a dosage late in the day to help them do their homework.”

Tatos wasn’t familiar with Guskiewicz’s work when he started reviewing the UNC documents, but as Tatos became aware of the alarming statistics – high ADHD rates, possible misuse of stimulants – it occurred to him that UNC football players were being used in concussion research. He then looked closer at research generated under Guskiewicz’s watch and found that UNC researchers, including Guskiewicz, failed to account for LD/ADHD as a modifying factor in published studies.

Periodically, Tatos posted portions of the documents on social media. Don Comrie began to follow Tatos’ social media posts and eventually reached out to him in early 2016 to discuss Tatos’ findings. The two began communicating regularly, leading to their collaborative effort published earlier this year.

One of the many studies that caught their eye was a 2007 paper written by Meghan McCaffrey, which used 43 UNC football players as test subjects. The paper, whose co-authors included Guskiewicz, was published in the journal Neurosurgery when McCaffrey (now Meghan Lewis) was a UNC graduate student. Tatos discovered a discrepancy between McCaffrey’s 2006 Master’s thesis and the paper she co-authored for Neurosurgery: Her Master’s thesis acknowledged the presence of LD/ADHD in her test group, but when the thesis was published in Neurosurgery, she and her co-authors did not disclose that information.

Lewis told The Athletic‘s Armen Keteyian that “there wasn’t really a whole lot of focus on the impact of any kind of ADHD/learning disability” when she was writing her Master’s thesis.

“I honestly don’t remember discussions about LD, any effects of ADHD,” says Lewis, a clinical associate professor in the athletic training program at Quinnipiac University. “I don’t know if it was a discussion we had, but it doesn’t stick out in my mind. I honestly can’t give you a reason as to why we didn’t put the specific numbers in … I’m not saying that it was important or not important. I’m just saying at that time that wasn’t my focal point.”

Disclosing variables in concussion research – such as athletes with LD/ADHD, and those using stimulant medication to treat such conditions – prevents biased results. When researchers are creating normative baselines for a certain population of football players, and if they don’t account for the players with those types of conditions, the averages can be skewed. A baseline test is like a profile of an athlete’s cognitive function and is usually administered before the season. If a player suffers a concussion or other head injury, the athlete’s post-injury test results are measured against the baseline.

One danger of not disclosing for variables like LD/ADHD is that potentially tainted research floods into the mainstream, where the data is cited by others and used to dictate protocols and treatment. Football players who have sustained concussions could be returning to the playing field earlier than they should be, for example.

It has long been standard practice to account for LD/ADHD in concussion research. Twenty years ago, Dr. Michael Collins, the director of the University of Pittsburgh’s Sports Medicine Concussion Program, co-authored a paper on concussion and sports published in the prestigious Journal of the American Medical Association. The Collins paper established a foundation for researchers to treat ADHD as a modifying factor in concussion research, and it has become an oft-cited paper in the field.

During a 2013 presentation for the Tennessee Psychological Association convention, Dr. Gary Solomon referenced the Collins paper in his slide presentation. “Since this 1999 study with collegiate football players, athletes with LD and ADD have been excluded from most concussion research studies,” wrote Solomon, the former co-director of the Vanderbilt (University) Sports Concussion Center and a former consulting neuropsychologist for the Tennessee Titans.

Guskiewicz declined to be interviewed by The Athletic, but issued a statement: “I stand by our concussion research 100 percent. Our research protocols go through a robust internal review process, and in most cases an additional external grant review process. Our research has been peer reviewed by hundreds of respected neuroscientists and sports medicine researchers before being published. I am proud of the work my colleagues at the Gfeller Center and other scholars who contributed to this work have done to help improve concussion prevention and care for athletes and service members. Every journal has its own disclosure policies; we have always fully complied with those guidelines.”

In 2015, he gave a videotaped deposition in the lawsuit between the parents of Derek Sheely and several defendants, including the NCAA. Sheely was a fullback at Frostburg (Md.) State University in 2011 when he died after sustaining a head injury during practice. (The Sheely family reached a $1.2 million settlement with the NCAA in 2016, according to the Baltimore Sun.) “I see value in some cases, especially in athletes that have learning disabilities or attention deficit disorders that the baseline testing is valuable,” Guskiewicz said in his deposition.

UNC is already one of the core schools participating in the CARE Consortium – a partnership between the Department of Defense and NCAA, which began in 2014 and has received $64 million in funding so far. Last year, the NFL awarded UNC-Chapel Hill part of a $14.7 million grant for a joint concussion/TBI study, giving Guskiewicz another sizeable chunk of money to channel into UNC’s research efforts.

UNC has been viewed as the gold standard in concussion research under Guskiewicz, but if Tatos and Comrie’s findings are accurate the trickle-down or domino effect could be significant. “There is the potential for research pollution. Leaving conflicts of interest aside, there is a research machine that manufactures doubt,” Tatos says.

Some of the biggest names associated with concussion research, including Guskiewicz, are attached to the CARE Consortium. Col. (Ret.) Dallas Hack, Brian Hainline, and Dr. Walter Koroshetz, the director of the National Institute of Neurological Disorders and Stroke (NINDS), are part of the CARE Consortium’s executive committee, while Guskiewicz and Steven Broglio, a University of Michigan professor, are CARE investigators and sit on the operating committee.

When presented with the Tatos and Comrie findings, Hack’s defense of past UNC studies not controlling for LD/ADHD or not disclosing those conditions altogether included identifying Tatos as someone “who doesn’t seem to have any expertise in the subject” of ADHD and concussion research.

Hack also believes that in this research field, ADHD is a “vastly overdiagnosed” condition. “I know the ADHD situation has been discussed in the larger context of the CARE Consortium, with people admonished to pay particular attention to not overdiagnose it,” says Hack.

Broglio says that accounting for LD/ADHD as a modifying factor in concussion studies is an unrealistic research tool, although he also says he was unaware that individuals who use stimulant medication to treat ADHD are excluded from the military. (One of the main roles of the CARE research is to inform both the collegiate athlete and military populations).

“If you start using these things as exclusion criteria, you’re down to zero participants, because everybody’s got something. How many people listen to Mozart, and Chopin and Bach? Or how many people read Steinbeck? Or look at Georgia O’Keeffe paintings? If I gave you a list of all the things that I think are going to influence cognitive functioning, that is all you would fill out,” says Broglio. “It’s not a practical way to approach clinical science.”

But earlier this year, an International Olympic Committee consensus statement co-authored by Hainline – a CARE executive committee member – says ADHD needs to be controlled for in concussion research, and other scientific and medical experts who have read Tatos and Comrie’s work see it as raising legitimate concerns about some of the concussion research coming out of UNC.

“The (Tatos/Comrie) article is extremely well done … the conclusions are so important. Not only should the authors of the poorly designed (UNC) studies be identified and brought to task but the journals that published the poorly designed studies are equally culpable,” says Dr. Wayne Gordon, for three decades the director of Mount Sinai’s Brain Injury Research Center in New York and now the Jack Nash Professor and vice-chair of the Department of Rehabilitation Medicine at Icahn School of Medicine.

In his 2013 email exchanges with Greg Aiello, the NFL’s communications director, prior to Roger Goodell’s visit to the UNC campus, Guskiewicz offered a phrase that Goodell would make his own:

“Science can be a game changer.”

It is a phrase loaded with possibility and harkens to the Time blurb about Guskiewicz. That is what the magazine called him – a “game changer” – and for years Guskiewicz has held a perch in concussion research that reflected that exalted status.

Dr. Koroshetz of the CARE Consortium expressed little concern that the paper authored by Tatos and Comrie will change that: “The folks we fund, we fund them because we think they have the highest integrity in terms of the science that they do.”

Counters Ted Tatos: “This is not a personal issue. I don’t even know these people. I’m looking at these documents, and I’m going, ‘Whoa.’ The facts are very vocal in this case. The documents speak for themselves.”

– Andrew J. Muscato and Armen Keteyian contributed to this story.

(Top photo of Kevin Guskiewicz: Gerry Broome / AP Photo)