Intended for healthcare professionals

Clinical Review ABC of complementary medicine


BMJ 1999; 319 doi: (Published 09 October 1999) Cite this as: BMJ 1999;319:973

"Only 20% of Western medicine is evidence-based"? Wrong.

While Vickers' and Zollman's article warrants criticism on several grounds, other correspondents have done an admirable job addressing most of the pertinent deficiencies. I'm writing to address a bit of "alt med misinformation" which, though exposed as such nearly five years ago, refuses to die.

In his letter of October 27, acupuncturist Wainwright Churchill tells us:

"One must remember that it has been estimated that only 20% of conventional medical practices have been ‘proven’ (e.g. by the U.S. Office of Technical Assessment)."

Likewise, on October 28, John P Heptonstall, Director of Morley Acupuncture Clinic and Complementary Therapy Centre tells us:

"Requiring 'evidence-based'(EB) information about any modality is noble and correct; 80% of WM [Western Medicine] is not yet EB yet it is subjected to multi billion pound funding."

Fortunately, the truth regarding this long-refuted but oft-repeated myth has finally begun to make inroads among advocates of scientific biomedicine. For instance, see:

Report Of The Ad Hoc Committee On Complementary Medicine To The Council Of The College Of Physicians And Surgeons Of Ontario, September 22, 1997

"The Committee notes that in a hearing before the U.S. Congress, Dr. Kerr White, the individual who originally made the statement, explained that it referred to a small 1963 study of prescribing practices by GP’s in a small northern British town and the correlation of their prescribing with evidence-based ideals. The results were never intended to be applied generally."


...And from the NCAHF Newsletter, Volume 18, Number 6 (November-December 1995)


Critics of standard medicine are fond of quoting a 1978 OTA report which stated that "only 10 to 20 percent of procedures currently used in medical practice have been shown to be efficacious by controlled trial."1 Promoters of questionable medicine used this "statistic" to justify their unproven "alternative" and "complementary" procedures. The OTA report did not reveal how the "10 to 20%" figure had been determined, but now Kerr L. White reveals that he was its source. White was responding to a British study in which the authors stated: "For many years clinicians have had to cope with the accusation that only 10-20% of the treatments they provide have any scientific foundation" [They had found that 82% of the primary treatments given to 109 patients during April, 1995, on whom a diagnosis had been reached, were scientifically proven.2] White disclosed that he based his 10-20% estimate on a 1963 paper 3 that reported on a survey of the prescribing practices of 19 family doctors in a northern British town for two weeks (one in December 1960, and another in March 1961). The survey wasn't trying to evaluate the science of medical practice. Its purpose was to look toward controlling prescribing costs in terms of "standard" (ie, "generic") versus "proprietary" drugs. The "intent" of eac h prescription was analyzed according to how specific it was for the condition. These were divided into categories of "standard" or "proprietary" drugs. Intent was "specific" for the condition for which it was prescribed only about 10% of the time; "probable" in about 22%; "possible" in 26%; "hopeful" in 28%; "placebo" in 10%; and, "not stated" in 3.6%. From these data White estimated that 10-20% of the medicine practiced was evidence-based, and that the combined placebo and Hawthorne effects accounted for another 20-40%; and the rest (which he refers to as a "mystery") accounts for 40-70%. White stated:

Some 20 years ago, as a member of the original Health Advisory Panel to the US Congressional Office of Technology Assessment I ventured the 10-20% figure again and invited anyone to provide more timely data. No one could. The figure was immortalized in OTA circles and publications for almost a decade. In countless addresses and conferences I often challenged others to provide better evidence but none was forthcoming. So the northern industrial town "armchair" assessment persisted.4

Little about the survey's setting was relevant to standard American medicine in 1978, much less today. Time-wise, the 1963 survey report was coincidental with the 1962 Harris-Kefauver Amendment that for the first time mandated premarketing efficacy for medications. The survey was done in England, which has no law comparable to the US Food, Drug & Cosmetic Act. White admits to the "armchair" quality of his statement. Why did no one challenge White's estimate? Most likely it was because no one was willing to make a statement that couldn't be substantiated scientifically. In short, they weren't as willing as he to be unscientific!

White created a myth damaging to standard medicine, and useful to the promoters of quackery. Should White be chastised for his indiscretion? The intent of the OTA Report was not to advocate an open marketplace, or that there be less science in healt h care. Its purpose was to find ways for improving the process through which the safety and efficacy of health care technologies are established. White merely was emphasizing deficiencies in the present system. Nevertheless, White can be criticized for inferring in a report to Congress that the survey results were representative of standard medical practice in the USA. Legislators need valid information to act in the best interest of the nation.

(1) US Congress, Office of Technology Assessment. Assessing the Efficacy and Safety of Medical Technologies. Sept, 1978, Wash, DC;
(2) Ellis et al. "Inpatient general medicine is evidence-based," The Lancet 1995;346:407-10;
(3) Forsyth, G. "An inquiry into the drug bill," Medical Care 1963;1:10-16;
(4) Letters to the editor, The Lancet 1995;346:838.


...And from the NCAHF Newsletter, Volume 19, Number 5 (September-October 1996)


In the Nov-Dec 1995, issue we reported that Kerr L. White, MD, had revealed that he was the likely source of the state ment in the 1978 OTA report that "only 10 to 20 percent of pro cedures currently used in medical practice have been shown to be efficacious by controlled clinical trial." White told NCAHF that the figure was used heuristically to stimulate the search for more accurate information. White says that he had no control over the fact that the OTA used his armchair estimate in its final report, and that neither he nor the OTA can be blamed for the abuse of the statement by quacks and the enemies of standard medicine. Neither he nor the OTA could anticipate how the statement was going to be abused by the enemies of science-based medicine. The intent of the OTA report was clearly to improve the scientific aspects of medical care, not to advocate an open door to unproven alternative and complementary medicine. After hearing White's side of the story, it is clear that he should not be blamed for either creating the myth that only 10-20% of standard medicine is scientifically proved, or for any of its fallout. White has always worked to strengthen the former st udents are leadi ng in the fields of health services research and evidence-based medicine. NCAHF regrets having placed this burden on White, and is pleased to know that no advocate of nonscientific medicine will find comfort in pursuing this statement to its source.

(1) U.S. Congress, Office of Technology Assessment, Assessing the Efficacy and Safety of Medical Technologies. Sept 1978, Wash, DC.


For those interested in a more detailed account of the genesis of the "15 to 20% EBM myth," (and the real percentage of EBM in modern practice), Prof David L. Sackett, Director of the Centre for Evidence-Based Medicine recently provided an excellent concise review on the "EBH Discussion Group." See:

In the allied worlds of "alternative medicine" and "post-modernism," "reality" and "the facts" seem to be "whatever you believe them to be." Not so in the worlds of scientific biomedicine and "reductionist science." It would be refreshing to hear Churchill, Heptonstall, and other ethical "alt med advocates" renounce the pernicious myth that "only 20% of Western Medicine is evidence-based." Hope springs eternal.

Best regards to all,

Robert Imrie, DVM

Director, NCAHF Task Force on Veterinary Pseudoscience
See: "The Entirely On-Line Alt Med Primer"

Competing interests: No competing interests

17 November 1999
Robert Imrie