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Correspondence |

Cognitive Biases or Inadequate Searching?Cognitive Biases or Inadequate Searching? FREE TO VIEW

Scott K. Aberegg, MD, MPH, FCCP; James O’Brien, MD
Author and Funding Information

From the SKA Critical Care Services LLC (Dr Aberegg); and Pulmonary, Critical Care, and Sleep Medicine, The Ohio State University Medical Center (Dr O’Brien).

Correspondence to: Scott K. Aberegg, MD, MPH, FCCP, SKA Critical Care Services, LLC, 1321 S 600 E, Salt Lake City, UT 84105; e-mail: scottaberegg@gmail.com


Financial/nonfinancial disclosures: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.


© 2012 American College of Chest Physicians


Chest. 2012;141(6):1636-1637. doi:10.1378/chest.11-3248
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To the Editor:

In a recent issue of CHEST (December 2011), Schwartzstein and Parker1 describe an interesting and physiologically nuanced clinical case and attribute a resident’s failure to solve it to cognitive biases. While we agree with the importance of cognitive biases in reasoning, we disagree with the attribution of the resident’s errors to availability and anchoring. We propose an alternative framework for evaluating his errors, one which may be more instructive for avoiding them in the future.

The authors’ attributions of cognitive biases in the case are based on an expository essay by Croskerry.2 Croskerry’s conceptions of cognitive biases deviate substantially from original descriptions, and he provides no empirical support for his altered formulations.3 The availability heuristic, as originally described, is a rule of thumb by which the frequency of an event is judged by the ease with which the event comes to mind4; usually, the frequency of a rare event is estimated to be higher than its actual frequency as when shark attacks are judged as more common than swimming pool drownings. Unless we are willing to attribute any poorly reasoned “first-stab” provisional diagnosis to availability bias, it would not appear to have been operative in the presented case. Anchoring refers to mental fixation on an irrelevant numerical anchor and the associated failure to sufficiently adjust subsequent numerical estimates away from the anchor.4 There are no numerical anchors in this case.

The resident’s errors in judgment are more adequately explained in the context of the search-inference framework5,6 which characterizes thinking as a search for goals, possibilities, and evidence conducted by cognitive system II.7 (This is contrasted with a system I or rapid and intuitive assessment with little deliberate thinking.7) With the goal of determining the cause of gas-exchange abnormalities in an ICU patient, the resident identified a common potential cause (pulmonary embolism), but his search for other possibilities was inadequate. It is not that the resident “could not think of another explanation,”1 but rather that he made no apparent effort to do so. This error of inadequate search (or inadequate effort) can be avoided by active and deliberate formulation of a comprehensive differential diagnosis, especially in cases that are not straightforward, such as this one.

The failure to dismiss pulmonary embolism (and to expand the search for other possibilities) was compounded by an inadequate search for evidence, represented by failure to discover the distended abdomen and declining respiratory system compliance as well as neglect of other evidence that both militated against pulmonary embolism and pointed to the correct diagnosis. Confirmation bias is present in this case but it is due to inadequate searching.

Anchoring and availability, depending on how you define them and what evidence you require, may or may not have been operative in this case. Still, these cognitive biases do little to elucidate the resident’s series of errors and omissions, and the admonition, “don’t focus too much on what you think of first,” seems unlikely to avert similar error sequences in the future because it offers no guidance on what to focus on instead. The resident would be better advised to slow down (less system I and more system II) and to search more deliberately for goals, possibilities, and evidence. Indeed, it was such effortful searching that led the authors to the correct diagnosis in this case, the resident’s unwavering enthusiasm for pulmonary embolism notwithstanding.

Schwartzstein RM, Parker MJ. Rising Paco2in the ICU: using a physiologic approach to avoid cognitive biases. Chest. 2011;1406:1638-1642. [CrossRef] [PubMed]
 
Croskerry P. The importance of cognitive errors in diagnosis and strategies to minimize them. Acad Med. 2003;788:775-780. [CrossRef] [PubMed]
 
Croskerry P. Achieving quality in clinical decision making: cognitive strategies and detection of bias. Acad Emerg Med. 2002;911:1184-1204. [CrossRef] [PubMed]
 
Tversky A, Kahneman D. Judgment under uncertainty: heuristics and biases. Science. 1974;1854157:1124-1131. [CrossRef] [PubMed]
 
Aberegg SK, O’Brien JM, Lucarelli M, Terry PB. The search-inference framework: a proposed strategy for novice clinical problem solving. Med Educ. 2008;424:389-395. [CrossRef] [PubMed]
 
Baron J. Thinking and Deciding. 2008; New York, NY Cambridge University Press
 
Kahneman D. Thinking, Fast and Slow. 2011; New York, NY Farrar, Straus and Giroux
 

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References

Schwartzstein RM, Parker MJ. Rising Paco2in the ICU: using a physiologic approach to avoid cognitive biases. Chest. 2011;1406:1638-1642. [CrossRef] [PubMed]
 
Croskerry P. The importance of cognitive errors in diagnosis and strategies to minimize them. Acad Med. 2003;788:775-780. [CrossRef] [PubMed]
 
Croskerry P. Achieving quality in clinical decision making: cognitive strategies and detection of bias. Acad Emerg Med. 2002;911:1184-1204. [CrossRef] [PubMed]
 
Tversky A, Kahneman D. Judgment under uncertainty: heuristics and biases. Science. 1974;1854157:1124-1131. [CrossRef] [PubMed]
 
Aberegg SK, O’Brien JM, Lucarelli M, Terry PB. The search-inference framework: a proposed strategy for novice clinical problem solving. Med Educ. 2008;424:389-395. [CrossRef] [PubMed]
 
Baron J. Thinking and Deciding. 2008; New York, NY Cambridge University Press
 
Kahneman D. Thinking, Fast and Slow. 2011; New York, NY Farrar, Straus and Giroux
 
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