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About the Site:

This is the blog for the book Medical Decision Making: A Physician's Guide, by Alan Schwartz and George Bergus (Cambridge University Press, 2008). The book is now available from Cambridge University Press

About the Authors:

Alan Schwartz, Ph.D. is an Associate Professor of Medical Education and Pediatrics at the University of Illinois at Chicago College of Medicine, where he teaches and conducts research on physician and patient decision making.

George Bergus, M.D., M.A. is the Dr. William and Sondra Myers Family Professor of Family Medicine at the University of Iowa Carver College of Medicine, and Co-Director of the Family Practice/Psychiatry Residency program. He holds a Certificate of Additional Qualification in Geriatrics.


Mammography and decision making

November 29th, 2009 by Alan Schwartz

A little history for the non-US readers: the U.S. Preventive Services Task Force (USPSTF) is an independent panel that reviews evidence and issues recommendations for preventive health care services.  They are sponsored by the U.S. Agency for Healthcare Research and Quality (AHRQ) but the panelists are physicians, nurses, and public health researchers  employed by universities and state health departments.

From 1989-2002, annual screening mammography was recommended for women at low risk of breast cancer starting at age 50 in the US. In 2002, USPSTF changed that recommendation to recommend mammography every 1-2 years for women starting at age 40. This change was scientifically contentious – there were questions about the data – but endorsed by cancer organizations. This month, USPSTF changed the recommendation back to starting at age 50. You can read the published recommendation here. This change is less scientifically contentious, but has been even more upsetting to cancer organizations and, in many cases, to women.

I’m going to tackle just a few of the key decision making questions here to try to clarify what’s going on. For example, I’m going to set aside questions of cost and of insurance coverage, which are significant issues, to focus only on the health questions, and only on women at low risk for breast cancer.
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Posted in Beyond the individual, Decision Making, Developing information, Understanding uncertainty | No Comments »

Helping students unlock the mysteries of Bayes

October 29th, 2009 by George Bergus

I am continually impressed by the link between seeing and understanding. This should not be surprising. How often have we had the experience of being told by a student (or colleague) that “I just don’t see it” after our failed attempts to explain a complex concept. If there is a relationship between seeing and understanding can we facilitate understanding by presenting the concept visually? This is not a novel idea but it is still one which often slips by me particularly in areas where I am facile (such as medical decision making).

Four times a year I lead a group third-year medical students through afternoon seminar on using test results in the diagnostic process. Although one could make this topic very broad, the focus of the seminar is essentially Bayes Theorem. There is plenty of evidence that this is a challenging topic for students in the health sciences (and practicing physicians). I certainly found it challenging when it was introduced to me in medical school. However, once mastered I had to wonder why students could not see how obvious Bayes Theorem is; it is only a simple mathematic transformation.  When teaching Bayes Theorem it always seemed to take me multiple attempts at the computation and providing explanations until a few of the group grasped the concept of probability revision. Most would leave bewildered.

In frustration, I searched for a better approach- I thought my students should be able to experience the wonder of probability revision and not the pain of elementary mathematics. The search led to a wonderful report about simplifying bayesian inference by making it visual. (S Krauss, L Martignon, U Hoffrage. Simplifying Bayesian Inference. Conference on Model-Based Reasoning in Scientific Discovery, 1998. Students still are required to perform simple mathematical computations but the visual presentation of Bayes Theorem allows the students to see where they are in the process. Once completed students can easily go back and review the steps they took.  This simple visual approach has turned afternoons of student frustration into afternoons of discovery where they come to “see” the importance of pre-test probability in interpreting a test result and “see” the importance of not only sensitivity but also specificity.

If you are facing a similar challenge in your teaching, I highly recommend that you take a look at this approach.

Posted in Understanding uncertainty | 3 Comments »

Lessons outside health care

June 18th, 2009 by Alan Schwartz

SMDM Annual Meeting Co-chairs Alan Schwartz and Brendan Delaney are pleased to announce the 2009 Annual Meeting will include a pre-meeting symposium on Saturday, October 17, 2009 in Hollywood, California, USA, titled, Getting Tools Used: Lessons from outside health care.

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Posted in Understanding uncertainty, Valuing health | 2 Comments »

Decision psychology and swine flu

May 5th, 2009 by Alan Schwartz

Behavioral economist (and 2009 President of the Society for Judgment and Decision Making) Dan Ariely appeared on NPR’s Marketplace to discuss reasons for the swine flu panic. Read or listen to the interview here.

He focuses on the difference between the value of an identified life and a statistical life, as well as the impact of uncontrollability on risk perception (part of the constellation of factors Paul Slovic has referred to as being associated with “dread risk”).

The availability heuristic is also relevant here – there is very little reporting of deaths associated with seasonal flu and a lot of reporting about potential new strains. This leads to an underestimate of the risk of seasonal flu, even in the young and elderly.

Posted in Beyond the individual, Decision Making, Understanding uncertainty, Valuing health | No Comments »

MD NetGuide and risk communication

April 26th, 2009 by Alan Schwartz

The cover story in the March 2009 issue of MD NetGuide is “The Risk of Risk: Explaining Difficult Concepts to Patients“, by G. Stephen Nace, a physician at the University of Illinois College of Medicine at Peoria who I recently had the pleasure to meet. Making Medical Decisions is prominently cited in the piece.

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Posted in Book news, Decision Making, Understanding uncertainty | No Comments »

Making Veterinary Decisions

March 10th, 2009 by Alan Schwartz

Many patients in many countries don’t pay the full cost of their medical care, which makes cost a less important factor in medical decision making, for both many patients and many physicians.

On the other hand, nearly everyone pays the full cost of their veterinary care, and taking your pet to the vet is a good time to think about how medical decisions should get made.

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Posted in Decision Making, Goals of medical care, Understanding uncertainty | 1 Comment »

Symposia from SJDM/SMDM online

December 15th, 2008 by Alan Schwartz

The 2008 annual meetings of the Society for Judgment and Decision Making (SJDM) and the Society for Medical Decision Making (SMDM) included a “symposium exchange”. A symposium by SJDM members was presented at SMDM 2008 (Pennsylvania, PA) and a symposium by SMDM members was presented at SJDM 2008 (Chicago, IL). At least one of the talks reported on a study of behavioral economics for weight loss that has recently received considerable media attention.

Videorecordings of the symposia are now available. You can find links at

Posted in Beyond the individual, Decision Making, Developing information, Understanding uncertainty, Valuing health | No Comments »

GUT decision-making

October 27th, 2008 by Alan Schwartz

I was recently at a workshop for National Science Foundation Principal Investigators focused on how to communicate research to the public and the media. One of the suggestions was to develop a three-word summary of the principle message of your research work. This is hard.

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Posted in Goals of medical care, Understanding uncertainty, Valuing health | 1 Comment »

Vaccines and evidence

September 22nd, 2008 by Alan Schwartz has recently reviewed a new book by pediatrician Dr. Paul Offit on the anti-MMR (and anti-thimerisol) vaccine movement. Back in February this year, a friend of mine wrote to me that she was “on the fence” about vaccinating her infant. As she put it, “Whom are we to believe?…I’d be interested in anything compelling on either side so I could just move on either way.  My confidence in institutions is at an all time low.”

My response to her (revised for this blog) reviewed some evidence, much of which also appears in the Salon article:

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Posted in Beyond the individual, Decision Making, Understanding uncertainty | 3 Comments »


April 4th, 2007 by Alan Schwartz

Subjective confidence is usually thought of as the degree to which a person believes they are correct about a judgment and are willing to say so. Confidence can be important when there is no objective guide to accuracy; in these cases, decision makers will usually prefer to make the judgment in which they have the greatest confidence; confidence can drive further behaviors (Weber, Böckenholt et al. 2000). Accordingly, there has been some concern that decision makers have appropriate levels of confidence in their judgments.

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