An Insider’s Look at What Happened When Chiropractic Was Evaluated Scientifically, and Why No One Remembers

I was a chiropractor between 1983 and 2010. I started at Palmer College of Chiropractic-West (PCCW) just as Bill Meeker, DC, Joe Keating, PhD, and Cynthia Dutro, DC, were ready to take chiropractic research seriously. They believed rigorous evidence could validate chiropractic and secure its place in mainstream health care. I was serious enough to write PCCW’s president, John Miller, DC, before enrolling, to gauge his commitment to research. He wrote back that research was essential for the profession to “survive and thrive.”

Many believed the profession would be remade by evidence, moved at last beyond its fallacious nineteenth-century vitalism. Today their success is, at best, equivocal. The most striking thing is that more than a decade of sustained and rigorous chiropractic research across North America, Europe, and Australia has largely vanished from professional memory. Students, practitioners, and researchers may now be retracing our ground, thinking the questions were never asked or never answered. And since the answers we uncovered were not what chiropractors wanted to hear, results were tossed into the elastic biopsychosocial and “more research is needed” bins.

Until then, chiropractic research had chased biomechanics and speculative models of how chiropractic worked—before establishing that it worked at all.

My entry into chiropractic owed less to ideology than to gravity. While visiting the Kentucky farm of a lifelong friend, I fell out of a tree. A few days later I developed an acute torticollis that made turning my head a serious negotiation, and someone at work recommended their chiropractor.

Improvement after treatment is not always improvement caused by treatment, since much of it arrives with time and attention. 

For the previous few years, I had lived with chronic throat-clearing and the sensation of something lodged deep in my airway. About three months into treatment, those symptoms and much of my asthma faded. The causal inference—the adjustments had cured me—is the one I would spend a career learning to question: improvement after treatment is not always improvement caused by treatment, since much of it arrives with time and attention.

Chiropractic Research 

The first thing I discovered at Palmer West was that chiropractic was not one profession but many: true believers, entrepreneurs, technicians, philosophers, clinicians, and a small but growing number of reformers who believed its future was science. Many of us believed that we might treat conditions like back pain better and safer than drugs or surgery. The curriculum was rigorous, but beneath it a larger argument was taking shape. What, exactly, was chiropractic, and what would happen if its claims were subjected to serious scrutiny?

Despite its modest resources and small size, PCCW became one of the first major centers of chiropractic research. The timing was good because the Wilk antitrust case against the American Medical Association was still unfolding. Judge Susan Getzendanner would ultimately rule, in 1987, that organized medicine had unlawfully restrained competition by attempting to isolate chiropractic. While she did not “declare” chiropractic scientifically valid, her ruling removed the legal barriers that had prevented the profession from competing on equal footing.

The Wilk ruling opened the door to legal collaboration between chiropractors and physicians, and other openings followed over the next several years. The Office of Alternative Medicine, funded by Congress in 1991 and staffed the following year, signaled that complementary therapies had become legitimate subjects for federally funded scientific investigation. By the mid-1990s, Andrew Weil and the University of Arizona were giving academic credibility to a new field of integrative medicine. Meanwhile, chiropractic colleges and organizations such as FCER were building research programs unlike anything the profession had previously attempted.

The doors to medical acceptance were opening. Research funding was increasing. If chiropractic possessed a distinctive clinical contribution, we finally had both the opportunity—and no longer the “chiropractic as victim” excuse—to demonstrate it. For the first time, failure to answer that question could no longer be blamed on exclusion from the scientific community.

Integrative Medicine 

It is difficult now to convey how electric alternative medicine felt in the late 1980s and early 1990s. Academic medical centers were beginning to acknowledge what patients had already decided for themselves: chiropractors, acupuncturists, massage therapists, nutritionists, meditation teachers, and other unconventional practitioners had become part of American health care whether universities approved or not. 

Then David Eisenberg and colleagues published their landmark study documenting the enormous use of unconventional therapies by Americans, often without informing their physicians.¹ The paper landed like a small earthquake. Alternative medicine ceased to be a fringe curiosity and became a public-health phenomenon. The professional opportunities followed quickly. 

Shortly after I arrived, the Foundation for Chiropractic Education and Research funded what was then the largest chiropractic research grant ever awarded to our team at PCCW: a $350,000 trial comparing chiropractic care, physical therapy, and standard medical management for low back pain. I was the research statistician: I wrote the power calculations and the analysis plan. The profession would finally be judged by the same standards as the rest of health care!

As I pushed for more research, word of my interests eventually reached Gene Carragee at Stanford University. Carragee—who served in the U.S. Army as a battalion and command surgeon and forward surgical team commander, and was later editor-in-chief of The Spine Journal—invited me to lunch at Stanford’s Faculty Club. I remember realizing almost immediately that my ambition had outrun my preparation.

A literature that will not resolve after enough well-powered attempts is not unfinished. It is null.

What surprised me was the generosity. Carragee encouraged me to send manuscripts before submission so he could strengthen them, later brought me into Stanford’s spinal research group and its conferences, and introduced me to residents and faculty. I had been handed a rare view of how major clinical research programs worked. My heart wanted it; my head was still occupied with chiropractic and its future.

The Stanford connections led to others. I was assigned to provide chiropractic students with medical rotations at PCCW. At the time, there were three general approaches to intractable back pain: anesthesiologists, orthopedists, and neurologists. Today, I would add physiatry.

I brought students on clinical rounds to observe intradiscal electrothermal therapy (IDET). I placed some in a San Francisco workers’ rehabilitation clinic. Some watched the action at Stanford’s Emergency Department. I was in discussion for several months about getting chiropractors certified in emergency medicine at Stanford University Medical Center, and physiatry training at the University of California San Francisco (UCSF). The former failed for liability reasons and the latter failed for the requirement that chiropractors would become licensed as phlebotomists, which chiropractic leadership deemed a bridge too far—too medical.

I became the first chiropractor appointed to Andrew Weil’s Program in Integrative Medicine at the University of Arizona. I developed and taught the program’s manual medicine curriculum; a course later delivered to physicians internationally. I also taught continuing medical education programs at El Camino Hospital, participated in research meetings at the Arizona Cancer Center, and wrote a two-part series on chiropractic for the Johns Hopkins Integrative Medicine newsletter.

In 1986 I visited Tyringham, an old English estate converted into an ambitious integrative health center backed by Sir Maurice Laing. The project brought physicians and complementary practitioners together to explore whether integrated care could improve patient outcomes. While in the UK, I proposed a program-evaluation approach to validating therapies to a group convened under the Prince of Wales’s interest in complementary medicine. I invited myself in through persistent phone calls to Mr. Colin Dove, Head of the British School of Osteopathy. As a follow-up, Mr. Dove said the committee ignored my suggestions because I was not on the agenda.

In all this, chiropractic leadership dug in their heels and showed no interest. Thus, the problem was never that chiropractic lacked opportunities. Every open door needed someone with the authority and resources to hold it open—to turn a visiting arrangement into a post, a collaboration into a program—and chiropractic’s leadership was simply not interested. It could not be done without institutional support. What unsettles me most now is how little of what happened survived as institutional memory. Today’s chiropractors know almost nothing of these attempts. That, as much as anything, is why I am writing this down.

Manipulation Works Best When Surrounded by Everything Except Manipulation 

During the 1980s and 1990s chiropractic researchers launched clinical trials, comparative-effectiveness studies, and collaborations with universities and medical centers.

Then, the larger, better-designed studies made the clinical picture go soft. Patients improved—sometimes substantially—but the improvement proved stubbornly hard to pin on manipulation. Natural history, spontaneous recovery, reassurance, exercise, attention, expectancy, and plain contextual healing kept blurring the causal thresholds.² Manipulation generally performed about as well as any other conservative care including placebo, and when superior, it closely tracked the false positive rate expected under null hypothesis significance testing.^3, 4 In fact, to this day you will see chiropractic research conclusions proudly assert that manipulation is no less effective than other treatments for low back pain, including controls—a damnation by faint self-praise.

The problem was not only scientific but psychological, cultural, and institutional, which is why supporters and critics could read the same trials as Rorschach blots and come away convinced of opposite conclusions. When one body of evidence underwrites both conclusions, the fault is rarely bias; more often the evidence was never built to answer the question asked of it.⁵ The remedy is unglamorous: decide in advance which single measure could settle the question, weigh several rival hypotheses at once,⁶ and recognize when further information can no longer move the decision.⁷ In short: name in advance the result that would change your mind. Chiropractic, though, thrived in the ambiguity. When outcomes were positive, manipulation worked; when they were negative, prejudice or incompetence was clearly afoot.

So the center of gravity in chiropractic research quietly retreated from the awkward clinical effectiveness question, towards safer, fundable territory: biomechanics, sensorimotor physiology, adverse-event surveillance, health-services research, and broad biopsychosocial models.

Does spinal manipulation itself produce large, reliable, clinically transformative effects beyond natural history and contextual healing?

I eventually tried to answer that question—at scale, assembling a meta-analysis of spinal manipulation for low back pain: a hundred and twenty randomized trials, some nineteen thousand patients, modeled against the natural history of recovery. The results did not rescue the story I had spent my youth defending. Once natural history and contextual healing were given their due, the slight effect we detected turned out to be natural history carrying manipulation for acute pain and a faint placebo carrying it for chronic pain.^8, 9 Years later, a contemporary from those reform days, chiropractor, influencer, and fellow researcher Greg Plaugher, remarked to me that “evidence-based chiropractic” was an old and abandoned paradigm.¹⁰

The strongest outcomes came not from an isolated mechanical input but from a comprehensive human encounter with many routes to recovery. 

Meanwhile the clinical literature kept telling the same story. In the modern military trials led by Christine Goertz—herself a symbol of the profession’s evolution—active-duty patients who received chiropractic care did better than those on usual medical care alone.¹¹ Pain, function, and satisfaction all improved: at first glance, exactly the evidence reformers hoped to see. 

Look closer, though, and the chiropractic “arm” was not manipulation but, in reality, the effect of repeated visits, education, exercise, reassurance, coaching, ergonomic advice, self-management support, and the whole atmosphere of attentive care. Patients improved; the contribution of manipulation itself stayed unknown. And when mechanistic studies looked for the distinctive physiological signature—balance, postural sway, neuromuscular response—the effects were weak, inconsistent, or absent.¹² The anticipated effects of chiropractic refused to show up. 

The strongest test arrived recently. In a trial published online in late 2025, a team led by Gert Bronfort reported on a thousand patients.¹³ Adults at elevated risk of chronic back pain were randomized to manipulation alone, a biopsychosocial self-management program, both, or guideline-based care. Over a year, manipulation by itself was statistically indistinguishable from ordinary medical care on pain and disability—half a century of hope for the adjustment, tested cleanly at last, returning null. A companion report the following year found that the self-management program outperformed both guideline-based medical care and manipulation alone!¹⁴

Which left an uncomfortable possibility, one that would have sounded like heresy in the reform years and gradually condensed in my mind into a single sentence: Manipulation works best when surrounded by everything except manipulation.

The strongest outcomes came not from an isolated mechanical input but from a comprehensive human encounter with many routes to recovery. 

There is another way to judge the reform movement. If research functions as intended, one would expect it to produce measurable changes in clinical practice. Yet after three decades, the average chiropractic office remains remarkably familiar. Technique systems continue to proliferate. Subluxation remains central in much of the profession. Weekend seminars still exert enormous influence. Clinical decisions are often shaped as much by tradition, philosophy, marketing, and personal experience as by systematic reviews. The profession unquestionably learned more about itself. Whether the profession itself changed very much is not so apparent.

Chiropractic research is alive and well in Denmark, New Zealand, and a handful of other centers, often more rigorous than anything the reform years produced. But the results of more research will not make spinal manipulation more acceptable. It cannot rescue a treatment this marginal; it will only measure it more precisely.

Palmer West closed its doors in 2025. And chiropractors who believe “more research is needed” continue to practice as they did a century ago, confident of eventual vindication. However, we did not leave a summary of what we found or did not find—no capstone or mile marker that said we did the work, and here is what we did or did not observe. So let this article stand as the mile marker: we did the work, and the work came back equivocal. That is harder to say than a clear finding, and easier to ignore. But a literature that will not resolve after enough well-powered attempts is not unfinished. It is null.