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Part 2: Blind Spots Can Kill Patients

January 12, 2011
by Joe Bormel
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Cognitive Errors–The Conclusions that Lead to Unintended Consequences

In part one of this series , I introduced the widely accepted premise that delivery of complete, accurate, up-to-date, and relevant information to care providers, surpassing today’s norms by using information technology, would lead to better care. Care is complex, of course. It’s not simply the challenge of getting a patient’s prior medical information to the clinician, although this is clearly a challenge. It’s the absence, for instance, of good, up-to-date problem lists and many disconnects in today’s medication reconciliation systems that create dangerous blind spots. Beyond the patient’s specific information, medical knowledge is both incomplete and incompletely disseminated. So, how much should we expect HCIT to improve the care we actually deliver?

Fortunately for all of us, several researchers, including Dr. Mark Graber, have studied exactly this issue in the domain of Internal Medicine. Writing with collaborators in 2005 for the “Archives of Internal Medicine, Diagnostic Error in Internal Medicine,” (full text here) he stated, “The goal of this study was to determine the relative contribution of system-related and cognitive components to diagnostic error, and to develop a comprehensive working taxonomy.” In 93 percent of cases reviewed, fault was identified in system-related and cognitive categories. Over 500 factors in these cases were noted to contribute. System-related factors contributed in 65 percent of the cases; cognitive factors in 74 percent. “The most common cognitive problems involved faulty synthesis.”

Premature closure, i.e. the failure to continue considering reasonable alternatives after an initial diagnosis was reached, was the single most common cause.

The punch line for me was, “Faulty or inadequate knowledge was uncommon.”

Graber has gone on since 2005 to describe the errors that contribute to the majority of cognitive errors, and elaborate the implications for medical education, as well as the structure of healthcare delivery systems. Patient safety and medical diagnostics error literature have conveyed that more than 30 biases and fallacies lead all of us, including doctors, to take correct information and come to incorrect conclusions. (Complete list with more background in Dennis Boyle's 2010 article here) As we roll-out HCIT with the goal of improving care, we need to evolve to not just delivering the capacity to address Meaningful Use; we need to factor into the designs of our care delivery environments the practices that will have the most impact on improving care. HCIT plays an important role, and cannot be blind to the cognitive realities highlighted by Graber, Berner, Gladwell, Boyle, and many others.

Cognitive Error Type


Improves with HCIT?

Aggregate bias:


The tendency for physicians to believe that aggregated data, such as those used to develop clinical practice guidelines, do not apply to their own individual patients.


Not directly.




The tendency to rely too heavily on one trait or piece of information when making decisions.


Not directly.


Ascertainment bias:


Occurs when a physician’s thinking is shaped by prior expectations, stereotypes, and biases.


Not directly.




The tendency to assign a probability to a disease according to vividness of memory.


Not directly.


Base rate neglect:


The tendency to base judgments on specifics, ignoring general statistical information.


Not directly.


Commission bias:


The tendency toward action rather than inaction stemming from either overconfidence or perceived pressure and desperation to “do something.”


Not directly. Could be made worse by HCIT.


Diagnostic creep:


Through the presence of medical intermediaries, what might have started as a possibility eventually becomes definite, and all other possibilities are excluded.


Not directly.

The table above shows a few of the 30 biases leading to the cognitive error problem. This is the first step toward thinking through what “clinical decision support” and clinical improvement programs are really needed. Therefore, do you agree it appears that earning and building the trust of clinicians will be a critical component to informing better decisions?

In the next in this series of posts, we’ll explore how to avoid these avoidable cognitive errors.

Joe Bormel, M.D., MPH
CMO & VP, QuadraMed

“Coming together is a beginning.

Keeping together is progress.

Working together is success.”

- Henry Ford

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