Written by Charles Sneiderman, MD PhD
A new Institute of Medicine report on medical error estimates that 5% of US adults who get outpatient care each year are incorrectly diagnosed. Thus the majority of adults will experience a medical diagnostic error during their lifetime. The IOM definition of diagnostic error is failure to establish an accurate and timely explanation of a patient’s health problem or to communicate that explanation to the patient.(1)
I believe that the method used to estimate the frequency of diagnostic error in this report is badly flawed. I say this because the major data source for the studies summarized was medical records. Outpatient medical records, even in this era of electronic record-keeping are notoriously incomplete. Clinicians get paid for providing care, not for documenting it. Medical records are highly distilled notes to remind the clinician of the patient’s findings and treatment in a language which is highly abbreviated and codified.
Diagnosis is an open-ended process; clinicians are required to report an interim conclusion summarized

One of the first demonstrations that computerized reminders improve physician adherence to clinical practice guidelines was published in 1977 by Clem McDonald’s group in Indiana.(2)
Clem had postdoctoral training at the Massachusetts General Hospital in Octo Barnett’s lab; Octo had developed the Computer Stored Ambulatory Record (COSTAR) which was also adopted by the Family Medicine Department at the Medical University of South Carolina where I did my residency in those years. I 
Computer assistance in medical diagnosis has a long history. When I first began my career at the National Library of Medicine over thirty five years ago, we funded a research project at the University of Pittsburgh in which the wisdom of Dr. Jack Myers, a highly respected diagnostician was programmed into a statistical matrix which, when fed the findings of the New England Journal of Medicine’s “case of the week” came up with the correct diagnostic conclusion more often than most recent graduates of medical residency training like myself at that time. There have been numerous such programs developed over the intervening years, but none have had widespread adoption because the process to input all the findings had to be done manually. The final frontier of computer assisted diagnosis is being explored today with the use of natural language processing to extract the findings from the text of clinicians notes in EMRs. Hopefully I will live to see the Holy Grail.
- Balough EP, Miller BT, Ball JR, et al., eds., Improving Diagnosis in Health Care, Washington: National Academy of Sciences, 2015.
- McDonald CJ, Murray R, Jeris D, Bhargava B, Seeger J, Blevins L. A computer-based record and clinical monitoring system for ambulatory care. Am J Public Health. 1977 Mar;67(3):240-5.



